2
3
The brightness of the bulbs is a qualitative comparison. Learners should use "bright, brighter, brightest" as a way to describe the glowing bulbs. The graph should show the quantitative data of the ammeter reading and the number of bulbs. If you do not have an ammeter to take readings, either do not draw a graph, or change the graph to a bar graph which has bright, brighter, brightest as the values on the y-axis. This is not a particularly useful graph but will give the learners a chance to practice drawing a bar graph and give them a visual representation of the decrease in current strength as the number of bulbs increases.
Draw a graph to show the relationship between the number of bulbs and the current.
These results are an example of possible results. The actual results obtained by the learners will differ but the trend should be similar. As the number of bulbs in series increases, both the ammeter reading and bulb brightness should decrease.
|
|
|
1 | brightest | 0,15 |
2 | bright | 0,07 |
3 | dimmest | 0,05 |
Using standard ammeters may not give perfect results and if the bulbs are allowed to heat up too much in between adding more bulbs, their resistance will be higher. It is important that the learners see a downward trend.
What happened to the brightness of the bulbs as the number of bulbs increased?
The bulbs got dimmer as more bulbs were added.
When you had two bulbs, did they glow with the same brightness, or was one brighter than the other?
The bulbs glowed with the same brightness.
When you had three bulbs, did they glow the same as each other or was one brighter than the others?
What do your answers to the previous questions tell you about the current in the series circuit?
If all the bulbs glow the same, it means that they all experience the same current. This means that the current is the same everywhere in a series circuit.
What happened to the reading on the ammeter as you added more bulbs in series?
The ammeter reading decreased.
CONCLUSION:
Based on your answers, what happened to the current when more bulbs were added in series?
As more bulbs were added, the current decreased.
Is your hypothesis accepted or rejected?
This answer will depend on the hypothesis written by the learner at the start of the investigation.
As more resistors are added in series, the total resistance of the circuit increases. As the total resistance increases, the current strength decreases. What would happen if we increased the number of cells connected in series? Would the current become larger or smaller? Let's investigate.
This investigation will show that adding more cells in series increases the current strength. Be careful with this activity because if you do not have enough resistance in your circuit, you can damage the torch light bulbs. Use at least two torch light bulbs or a torch light bulb and a resistor in order to keep the resistance high enough. If you have ammeters, you can use quantitative data to show that adding more cells in series increases the current strength. If you do not have ammeters, then use the brightness of the bulbs as qualitative data. Use terms such as dim, bright, brightest. The learners will not be able to draw effective graphs with the qualitative data but you could give them the example data in the teacher's guide and ask them to draw a line graph if they need practice.
AIM: To investigate the effect of increasing the number of cells connected in series on the electric current strength.
HYPOTHESIS: Write a hypothesis for this investigation. Remember to mention how the increase in the number of cells will affect the current strength.
This answer is learner-dependant. They must mention how the dependent variable will be affected by the independent variable. Remember that the hypothesis does not need to be factually correct. They will prove or disprove it by completing the investigation. Here is an example of a possible hypothesis: As the number of cells connected in series increases, the current strength increases.
MATERIALS AND APPARATUS
Observe the brightness of the bulbs and record the ammeter reading in the table of results. Draw a circuit diagram.
Record the ammeter reading in the table of results. Draw a circuit diagram.
These results are example results. The actual results obtained by the learners will differ but the trend should be similar. As the number of cells increases, both the ammeter reading and the bulb brightness should increase.
|
|
|
1 | dimmest | 0.07 |
2 | bright | 0.15 |
3 | brightest | 0.22 |
As the number of cells connected in series increases, so does the current strength.
This answer depends on the learner's original hypothesis.
We have seen that increasing the number of cells in series increases the current, but increasing the number of resistors decreases the current.
We will now investigate the current strength at different points in a series circuit.
The first investigation looked at the decrease in current strength when more resistors were connected in series. This investigation confirms that the current strength is the same at all points in a series circuit. This is an optional investigation. This can be a demonstration if your equipment is limited. This is a good opportunity for group work, but make sure that each learner is able to connect an ammeter correctly and understands the ammeter scale.
INVESTIGATIVE QUESTION: Is the current strength the same at all points in a series circuit?
HYPOTHESIS: Write a hypothesis for this investigation. What do you think will happen in this investigation?
This is a learner-dependant answer. Learners need to mention the independent and dependent variables. The dependent variable will change as the independent variable is changed.
Here are two examples of an acceptable hypothesis:
Measure the current strength using the ammeter. Draw a circuit diagram of this set up.
Complete the following table:
|
|
Between positive terminal of cell and first bulb | |
Between two bulbs | |
Between negative terminal of cell and last bulb |
The ammeter readings should be the same at any point in the series circuit.
CONCLUSIONS:
Write a conclusion based on your results.
The current strength is the same at any point in a series circuit.
Is your hypothesis true or false?
In a series circuit, there is only one pathway for the electrons to move through. The current strength is the same everywhere in that pathway.
What have we learned about series circuits?
There is only one pathway for the electrons to follow.
The current flows at the samestrength everywhere in a series circuit, because there is only one pathway. We say that the current is the same at all points in the circuit.
If you add more resistors in series, the current in the whole circuit decreases .
Why does the current stay the same at all points? Let's think about how electric current moves through a circuit. Do you remember that we spoke about the delocalised electrons in metals in the last chapter?
Animation showing the movement of electrons. http://www.schoolphysics.co.uk/animations/Electric_current/index.html
The electrons in a conductor normally drift in various different directions within a metal, as shown in the diagram.
When we build a closed circuit with a cell as an energy source, the electrons will all begin to move towards the positive side of the cell. The rate at which the electrons move, is determined by the resistance of the conductor.
There are electrons everywhere in the conducting wires and electrical components. When the circuit is closed, all the electrons start moving in the same general direction at the same time . This is why a light bulb turns on immediately when you close the switch.
Flip the switch and watch the electrons with this simulation. [link] http://phet.colorado.edu/en/simulation/signal-circuit
The simulation identified in the visit box helps to demonstrate how a light bulb turns on immediately when the switch is turned on.
In a series circuit, all the electrons travel through every component and wire as they travel through the circuit. All the electrons experience the same resistance and so they all move at the same rate.
This means that in the diagram below, the readings on all three ammeters will be the same, so: A 1 = A 2 = A 3
Parallel circuits offer more than one pathway for the electrons to follow. When constructing a parallel circuit, we say that components are connected in parallel .
Look at the diagram which shows how two light bulbs are connected in parallel.
How can you tell whether or not a circuit is connected in series or in parallel? Let's look at some circuit diagrams to tell the difference.
INSTRUCTIONS:
Look at the following circuits and decide which are in series and which are in parallel. The series circuits will only offer one pathway, but the parallel circuits will have more than one pathway for the electrons to follow.
series | parallel |
parallel | series |
Let's investigate how parallel circuits work.
This investigation will show the learners that increasing the number of resistors in parallel to each other, causes the overall resistance of the circuit to decrease and the current strength to increase. There is no need to discuss how to calculate the effective resistance of a parallel circuit. The learners just need a qualitative understanding.
AIM: To investigate the effect of adding resistors in parallel on the current strength.
If you do not have physical apparatus for this investigation but you do have internet access, use the PhET simulations found here: http://phet.colorado.edu/en/simulation/circuit-construction-kit-dc
This is a learner dependant answer. Learners need to mention the independent and dependent variables. The dependent variable will change as the independent variable is changed.
It is important that the torch bulbs are the same resistance and not randomly selected. The switch and ammeter are not strictly necessary for this experiment. They can be left out if you don't have enough switches or ammeters.
Note how brightly the bulb is shining and record the ammeter reading. Draw a diagram of your circuit.
The brightness of the bulbs is a qualitative description. The learners should use "bright, brighter, brightest" in order to describe the glowing bulbs.
The graph will show the relationship between the main current (reading on the ammeter) and the number of bulbs connected in parallel. As more bulbs are connected in parallel, the current strength should increase because the overall resistance of the circuit decreases. This means that the graph should be a straight line with an increasing trend. Standard ammeters may not be accurate enough to produce a perfectly straight line. This is not as important as seeing the upward trend.
These results are just an example. The actual results will depend on the circuit set up by the learner.
|
|
|
1 | dimmest | 0.15 |
2 | brighter | 0.3 |
3 | brightest | 0.45 |
The bulbs got brighter as more bulbs were added.
When you had two bulbs, did they glow with the same brightness or was one brighter than the other?
When you had three bulbs, did they glow the same brightness or was one brighter than the others?
What do your answers to the previous questions tell you about the current in the parallel branches of the circuit?
As all the bulbs are identical, if they all glow the same brightness, then they all experience the same current. This means that the current is the same in each branch.
What happened to the reading on the ammeter as you added more bulbs in parallel?
The ammeter reading increased.
Based on your answers, what happened to the current when more bulbs were added in parallel?
As more bulbs were added, the current increased.
As more resistors are added in parallel, the total current strength increases. The overall resistance of the circuit must therefore have decreased. The current in each light bulb was the same because all the bulbs glowed with the same brightness. This tells us that the current of electrons must have split up and moved through each of the branches.
We can also connect cells in parallel. What would happen if we increased the number of cells connected in parallel? Would the current get stronger or weaker?
AIM : To investigate how increasing the number of cells connected in parallel affects the current strength in a circuit.
This is a learner-dependent answer. Learners need to identify the independent and dependent variables. The dependent variable will change as the independent variable is changed.
The ammeter is not essential to the experiment. The brightness of the bulb can serve as a qualitative measure.
Set up a circuit which has one cell, the ammeter and the torch light bulb in series with each other. Draw a circuit diagram of your circuit.
Connect another cell in parallel with the first cell. To connect the second cell in parallel, connect a wire from the positive terminal of the first cell to the positive terminal of the second cell. Connect another wire between the negative terminal of the first battery and the negative terminal of the second battery. Draw a circuit diagram of your circuit.
Connect a third cell in parallel to the other two cells. Draw a circuit diagram of your circuit.
The brightness of the bulbs is a qualitative description. The learners should use "bright, brighter, brightest" in order to describe the glowing bulbs. The ammeter readings should stay the same.
What did you notice about the brightness of the bulbs?
The brightness of the bulbs should not change.
What did you notice about the ammeter readings?
The ammeter readings are the same.
What conclusion can you draw from your results?
Adding cells in parallel does not change the overall current strength.
Adding cells in parallel has no overall effect on the current strength. The current strength stays the same if you add cells in parallel.
We saw that the current strength increased when bulbs were connected in parallel. However, we were only testing the current strength at one point in the parallel circuit. How does the current compare in the different pathways of the circuit? Let's do an investigation to find out.
The first investigation looked at the increase in current strength when more resistors were connected in parallel. This investigation confirms that the current strength is not the same at all points in a parallel circuit. This is a good opportunity for group work, but make sure that each learner is able to connect and read an ammeter correctly. If you do not have enough equipment to allow for small groups to build the circuits, you can rather use this investigation as a demonstration. Perhaps give several learners an opportunity to come up to the front and help to connect the ammeters.
INVESTIGATIVE QUESTION: Is the current strength equal at all points in a parallel circuit?
|
|
between the cell and first pathway | |
in the first pathway | |
in the second pathway | |
in the third pathway | |
between the cell and the first pathway |
These are some example readings to show the trend:
|
|
between cell and first pathway | 0.9 |
in the first pathway | 0.3 |
in the second pathway | 0.3 |
in the third pathway | 0.3 |
between the cell and the first pathway | 0.9 |
If you do not use identical bulbs, then the readings in each of the branches will not be identical, but they will add up to reading in the main branch. If possible, it is worthwhile to demonstrate this to learners.
The current strength is not the same at all points in a parallel circuit. If the bulbs are identical, then the current is the same in the three branches, however the current in the main part of the circuit is greater than that in the individual pathways. The current in the main part of the circuit is the sum of the currents in the pathways.
What have we learned about parallel circuits?
There is more than one pathway for the current to follow.
If you add more resistors in parallel, the total current supplied by the cell in the circuit increases .
Why does the current divide when offered an alternative pathway?
Imagine that you are sitting in a school hall during assembly. You are bored and waiting for it to end so that you can go out to break to chat to your friends. There is only one exit from the hall. When you are dismissed, everyone has to exit through the same door. It takes a while because only some learners can leave at a time.
Now imagine that there is a second door that is the same as the first door. Now you and your friends have a choice of which door to go through. The speed at which the learners exit the hall will increase and some of you will exit through the first door while others will exit through the second door. No one can go through both doors at the same time.
This is similar to the way current behaves when in a parallel circuit. As the electrons approach the branch in the circuit, some electrons will take the first path and others will take the other path. The current is divided between the two pathways.
In the following circuit A1 = A4 and A1 = A2 + A3 and A4 = A2 + A3
We have looked at how resistors and cells behave in series and parallel circuits. Let's look at how different metals conduct electricity. All conductors have some resistance in a circuit. Are some metals better conductors of electricity than others?
Let's have a look at which metals offer more resistance than others to the flow of charge (current) through an electric circuit .
This activity only compares the effect of the type of material on resistance. The other factors that affect resistance will be covered in the Grade 9 Energy and Change syllabus.
Each metal will have a particular resistance based on the resistivity. You do not need to measure the resistance of each metal, all that is required is a qualitative description of the light bulb. The brighter the light bulb, the higher the current. If there is a high current it means that there is little resistance. So the brighter the bulb glows, the less resistance offered by the metal wire. The learners may make small mistakes if the brightness of the bulbs is difficult to distinguish.
Use whichever metal wires you have available. Try to get copper and nickel. You could twist aluminium foil into a wire (just make sure it is the same length and approximate thickness as the other metals). Aluminium wire will often ignite if placed in a circuit so test it beforehand and make sure that it does not get too hot. If you use the materials listed below, then nichrome will have the highest resistance, followed by zinc, then aluminium and copper has the lowest resistance of the four.
The actual length of wire that you use is not important, but they should all be the same length and thickness. If you cannot find these metals, any other combination of metals can be successfully used.
INSTRUCTIONS
Observe the brightness of the bulb.
Draw a circuit diagram of your apparatus.
An example circuit diagram with the break in the circuit where metals are to be tested shown on the left.
Why can we use the brightness of the bulb to qualitatively measure resistance?
High resistance opposes the movement of electrons, decreasing the current so there is less energy for the light bulb. The higher resistance wire will cause the bulb to be dimmer than the lower resistance wire.
List the metals in order of increasing resistance.
Copper, aluminium, zinc and nichrome.
Why do you think copper is used for connecting wires in electrical circuits?
Copper has an extremely low resistance, and so has a minimal effect on the overall resistance of the circuit. Other materials would add to the overall resistance of the circuit, decreasing the maximum possible current in that circuit.
There are several factors which influence the amount of resistance a material offers to an electric current. We have seen that the type of material is one of those factors.
In Gr 9 we will look at the other factors that influence resistance. If you want to see the content in other grades, remember that you can visit www.curious.org.za
Light bulbs are not the only devices used in electrical circuits. Devices that use electrical energy to function, including light bulbs, are called output devices. Let's look at some other common examples of output devices.
LEDs are widely used electronic devices. They are small lights but they do not have a filament like an incandescent bulb has. They therefore cannot burn out, as there is no filament to wear out, and they do not get as hot. LEDs are used in electronic timepieces, high definition televisions and many other applications. Larger LEDs are also replacing traditional light bulbs in many homes because they do not use as much electricity. They last longer than incandescent bulbs and are more efficient.
In the last chapter, we looked at the energy transfers in an electrical system. We will now represent energy transfer within electrical systems in a different way. We will apply this new representation to the difference between energy outputs in an LED and an incandescent light bulb.
Sankey diagrams were first introduced in the Gr 7 CAPS workbook as a way of representing the transfers of energy within a system, specifically focusing on the transfer of input energy to useful and wasted output energy. They provide a very clear illustration of the process. This links back to the previous chapter to reinforce learning.
You might have drawn Sankey diagrams in Grade 7. If not, here is some quick revision.
In an energy system, input energy is transferred to useful output energy and wasted output energy. A Sankey diagram is a visual and proportional representation of the energy transfers that happen in a system.
For example, a kettle uses about 2000 J of input energy, but only about 1400 J is used to heat the water. The remaining 600 J is wasted as sound. Here is the Sankey diagram to represent the energy transfer.
Remember that energy is measured in joules (J).
We will now compare an LED with an incandescent light bulb.
Draw a Sankey diagram for an LED if the input energy is 100 J, 75 J of energy is used to produce light and the rest is lost as heat.
Draw a Sankey diagram for a filament light bulb if the input energy is 100 J, the wasted heat energy is 80 J and the rest produces light.
Which bulb do you think is more efficient? Explain your answer.
The LED bulb is more efficient as more of the input energy is transferred to useful output (light) than is wasted as heat. In the filament light bulb, much more energy is wasted as heat.
Can you think of any other output devices? Make a list of as many as you can.
Some are: motors, buzzers, beepers.
The timeline does not need to be too specific. We want learners to realise that this was not an overnight discovery, but involved many people over a significant time. Here are some pertinent facts. This list is not complete and not all of the dates are necessary. Another useful resource is available here: http://www.timetoast.com/timelines/118814
An electricity timeline animation. http://resources.schoolscience.co.uk/britishenergy/14-16/index.htm
Write a short paragraph describing the career. Include information on how one can study or prepare for your chosen career.
The Eskom website has information regarding various careers and the internet has many different sources.
Series | Parallel | Series |
Parallel | Series | Parallel |
Look at the three circuit diagrams. Rank the circuits from brightest bulb to dimmest bulbs. [3 marks]
Brightest, bright, dim
Explain your choices in the previous question. [5 marks]
The first circuit has the brightest bulb because it has the least resistance and so it has the highest current. The third circuit has the highest resistance because it has two resistors connected in series with the light bulb. The more resistors connected in series, the higher the resistance and the lower the current.
Look at the three circuit diagrams. Rank the circuits from brightest bulb(s) to dimmest bulb(s). [3 marks]
Dimmest, bright, brightest
The third circuit will have the brightest bulb because adding resistors in parallel lowers the overall resistance in the circuit. The current is therefore greater and the bulb shines brighter. The first circuit is the dimmest because it has no parallel branches, and so offers the highest resistance.
Look at the circuit diagram below. Each light bulb is identical.
Is this a series or parallel circuit? Explain your answer. [2 mark]
How do the brightness of bulbs A, B and C compare? (which is the brightest?) [3 marks]
What would happen to the brightness of the bulbs if the switch was opened? Explain your answer. [5 marks]
This circuit has both series components (the cell and bulb A are in series) and a parallel branch consisting of bulb B and C.
Bulb A is the brightest, Bulbs B and C would have the same brightness as each other.
If switch S is opened, then bulb C will not glow. Bulbs A and B would now have equal brightness but they would be dimmer than when the switch was closed. A and B would now be in series with each other and there is no parallel branch. The overall resistance of the circuit would therefore be higher, resulting in a smaller current.
Study the following diagram.
What is the relationship between the ammeter readings on A1 and A4? In other words, how do the current strengths compare at these points in the circuit? Explain your answer. [3 marks]
What is the relationship between the ammeter readings on A1, A2 and A3? In other words, how do the current strengths compare at these points in the circuit? Explain your answer. [3 marks]
A1 = A4. The total current flows through the circuit at both of these points.
A1 = A2 + A3. The current splits between parallel branches in a circuit.
Total [38 marks]
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Published on 6 May 2022 by Shona McCombes .
A hypothesis is a statement that can be tested by scientific research. If you want to test a relationship between two or more variables, you need to write hypotheses before you start your experiment or data collection.
What is a hypothesis, developing a hypothesis (with example), hypothesis examples, frequently asked questions about writing hypotheses.
A hypothesis states your predictions about what your research will find. It is a tentative answer to your research question that has not yet been tested. For some research projects, you might have to write several hypotheses that address different aspects of your research question.
A hypothesis is not just a guess – it should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations, and statistical analysis of data).
Hypotheses propose a relationship between two or more variables . An independent variable is something the researcher changes or controls. A dependent variable is something the researcher observes and measures.
In this example, the independent variable is exposure to the sun – the assumed cause . The dependent variable is the level of happiness – the assumed effect .
Step 1: ask a question.
Writing a hypothesis begins with a research question that you want to answer. The question should be focused, specific, and researchable within the constraints of your project.
Your initial answer to the question should be based on what is already known about the topic. Look for theories and previous studies to help you form educated assumptions about what your research will find.
At this stage, you might construct a conceptual framework to identify which variables you will study and what you think the relationships are between them. Sometimes, you’ll have to operationalise more complex constructs.
Now you should have some idea of what you expect to find. Write your initial answer to the question in a clear, concise sentence.
You need to make sure your hypothesis is specific and testable. There are various ways of phrasing a hypothesis, but all the terms you use should have clear definitions, and the hypothesis should contain:
To identify the variables, you can write a simple prediction in if … then form. The first part of the sentence states the independent variable and the second part states the dependent variable.
In academic research, hypotheses are more commonly phrased in terms of correlations or effects, where you directly state the predicted relationship between variables.
If you are comparing two groups, the hypothesis can state what difference you expect to find between them.
If your research involves statistical hypothesis testing , you will also have to write a null hypothesis. The null hypothesis is the default position that there is no association between the variables. The null hypothesis is written as H 0 , while the alternative hypothesis is H 1 or H a .
Research question | Hypothesis | Null hypothesis |
---|---|---|
What are the health benefits of eating an apple a day? | Increasing apple consumption in over-60s will result in decreasing frequency of doctor’s visits. | Increasing apple consumption in over-60s will have no effect on frequency of doctor’s visits. |
Which airlines have the most delays? | Low-cost airlines are more likely to have delays than premium airlines. | Low-cost and premium airlines are equally likely to have delays. |
Can flexible work arrangements improve job satisfaction? | Employees who have flexible working hours will report greater job satisfaction than employees who work fixed hours. | There is no relationship between working hour flexibility and job satisfaction. |
How effective is secondary school sex education at reducing teen pregnancies? | Teenagers who received sex education lessons throughout secondary school will have lower rates of unplanned pregnancy than teenagers who did not receive any sex education. | Secondary school sex education has no effect on teen pregnancy rates. |
What effect does daily use of social media have on the attention span of under-16s? | There is a negative correlation between time spent on social media and attention span in under-16s. | There is no relationship between social media use and attention span in under-16s. |
Hypothesis testing is a formal procedure for investigating our ideas about the world using statistics. It is used by scientists to test specific predictions, called hypotheses , by calculating how likely it is that a pattern or relationship between variables could have arisen by chance.
A hypothesis is not just a guess. It should be based on existing theories and knowledge. It also has to be testable, which means you can support or refute it through scientific research methods (such as experiments, observations, and statistical analysis of data).
A research hypothesis is your proposed answer to your research question. The research hypothesis usually includes an explanation (‘ x affects y because …’).
A statistical hypothesis, on the other hand, is a mathematical statement about a population parameter. Statistical hypotheses always come in pairs: the null and alternative hypotheses. In a well-designed study , the statistical hypotheses correspond logically to the research hypothesis.
If you want to cite this source, you can copy and paste the citation or click the ‘Cite this Scribbr article’ button to automatically add the citation to our free Reference Generator.
McCombes, S. (2022, May 06). How to Write a Strong Hypothesis | Guide & Examples. Scribbr. Retrieved 19 August 2024, from https://www.scribbr.co.uk/research-methods/hypothesis-writing/
Other students also liked, operationalisation | a guide with examples, pros & cons, what is a conceptual framework | tips & examples, a quick guide to experimental design | 5 steps & examples.
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By Tim Jolliff
Engage learners in the experimental process as they develop a hypothesis and plan an investigation
This resource accompanies the article Understanding the hypothesis , part of the Teaching science skills series, from Education in Chemistry.
1 Make predictions using your scientific knowledge and use them to form a hypothesis.
2 Plan an appropriate investigation to test your predictions.
Download the slides as PowerPoint and pdf , teacher notes as Word and pdf and student worksheet as Word and pdf .
Experiments ‘to show’ can be frustrating for learners if they already know what the experiment will show. The approach here is to change the experiment into one where they will not know what happens.
Learners have to use critical thinking to evaluate the alternative suggestions in the concept cartoon. They are then asked to formulate a hypothesis based on their own ideas about what will happen. They will need experimental data in order to test their prediction.
As learners are asked to plan an investigation to test their hypothesis they are prompted to think about what makes a fair test and how to get reliable data.
This could be used to follow on from a class investigation into the effect of beaker size on the length of time the candle burnt. The slides can be used to guide a class discussion, in combination with or as an alternative to the worksheets. Give learners time to read the concept cartoon and consider their own ideas, then discuss and work towards agreeing on a hypothesis to test.
Alternatively, learners can work through the worksheet in groups, or independently as a homework task.
If the learners plan and carry out their own investigations this will be an activity for a whole lesson or even two. Otherwise all or part can be used as an activity at the start or end of a lesson.
There is an opportunity to evaluate some real experimental data (this might motivate learners to carry out the experiment to obtain better evidence). Learners are then asked to briefly think about the difficulties of showing only slight effects in results, as in medical research.
The follow-up task asks learners to use creative skills to produce their own concept cartoons. You can show learners more examples of concept cartoons from our collection .
This activity was created to be challenging, requiring learners to use critical thinking. By structuring as a class discussion you can use the discussion guidance in the teacher notes to offer prompts or ask questions to help guide learners needing more support. Alternatively, asking learners to work in small groups for some parts of the activity will give them a chance to support one another. More confident learners could complete the worksheet independently.
Answers and discussion guidance can be found in the teacher notes.
Candle investigation: hypothesis and planning - teacher notes, candle investigation: hypothesis and planning - student worksheet, additional information.
This resource was originally created by the author as part of our Chemistry for the gifted and talented collection. It has been updated and made more accessible.
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Use this reworking of the classic non-burning £5 note demonstration to explore combustion with learners aged 11–16 years
Only registered users can comment on this article., more resources.
By Lyn Nicholls
Identify learning gaps and misconceptions with this set of worksheets offering three levels of support
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Course: biology archive > unit 1, the scientific method.
1. make an observation., 2. ask a question., 3. propose a hypothesis., 4. make predictions., 5. test the predictions..
Practical possibility, building a body of evidence, 6. iterate..
An overview of the research hypothesis, different types of hypotheses, variables in a hypothesis, how to formulate an effective research hypothesis, designing a study around your hypothesis.
The scientific method can derive and test predictions as hypotheses. Empirical research can then provide support (or lack thereof) for the hypotheses. Even failure to find support for a hypothesis still represents a valuable contribution to scientific knowledge. Let's look more closely at the idea of the hypothesis and the role it plays in research.
As much as the term exists in everyday language, there is a detailed development that informs the word "hypothesis" when applied to research. A good research hypothesis is informed by prior research and guides research design and data analysis , so it is important to understand how a hypothesis is defined and understood by researchers.
A hypothesis is a testable prediction about an outcome between two or more variables . It functions as a navigational tool in the research process, directing what you aim to predict and how.
In research, a hypothesis serves as the cornerstone for your empirical study. It not only lays out what you aim to investigate but also provides a structured approach for your data collection and analysis.
Essentially, it bridges the gap between the theoretical and the empirical, guiding your investigation throughout its course.
If you are studying the relationship between physical exercise and mental health, a suitable hypothesis could be: "Regular physical exercise leads to improved mental well-being among adults."
This statement constitutes a specific and testable hypothesis that directly relates to the variables you are investigating.
A good hypothesis possesses several key characteristics. Firstly, it must be testable, allowing you to analyze data through empirical means, such as observation or experimentation, to assess if there is significant support for the hypothesis. Secondly, a hypothesis should be specific and unambiguous, giving a clear understanding of the expected relationship between variables. Lastly, it should be grounded in existing research or theoretical frameworks , ensuring its relevance and applicability.
Understanding the types of hypotheses can greatly enhance how you construct and work with hypotheses. While all hypotheses serve the essential function of guiding your study, there are varying purposes among the types of hypotheses. In addition, all hypotheses stand in contrast to the null hypothesis, or the assumption that there is no significant relationship between the variables .
Here, we explore various kinds of hypotheses to provide you with the tools needed to craft effective hypotheses for your specific research needs. Bear in mind that many of these hypothesis types may overlap with one another, and the specific type that is typically used will likely depend on the area of research and methodology you are following.
The null hypothesis is a statement that there is no effect or relationship between the variables being studied. In statistical terms, it serves as the default assumption that any observed differences are due to random chance.
For example, if you're studying the effect of a drug on blood pressure, the null hypothesis might state that the drug has no effect.
Contrary to the null hypothesis, the alternative hypothesis suggests that there is a significant relationship or effect between variables.
Using the drug example, the alternative hypothesis would posit that the drug does indeed affect blood pressure. This is what researchers aim to prove.
A simple hypothesis makes a prediction about the relationship between two variables, and only two variables.
For example, "Increased study time results in better exam scores." Here, "study time" and "exam scores" are the only variables involved.
A complex hypothesis, as the name suggests, involves more than two variables. For instance, "Increased study time and access to resources result in better exam scores." Here, "study time," "access to resources," and "exam scores" are all variables.
This hypothesis refers to multiple potential mediating variables. Other hypotheses could also include predictions about variables that moderate the relationship between the independent variable and dependent variable .
A directional hypothesis specifies the direction of the expected relationship between variables. For example, "Eating more fruits and vegetables leads to a decrease in heart disease."
Here, the direction of heart disease is explicitly predicted to decrease, due to effects from eating more fruits and vegetables. All hypotheses typically specify the expected direction of the relationship between the independent and dependent variable, such that researchers can test if this prediction holds in their data analysis .
A statistical hypothesis is one that is testable through statistical methods, providing a numerical value that can be analyzed. This is commonly seen in quantitative research .
For example, "There is a statistically significant difference in test scores between students who study for one hour and those who study for two."
An empirical hypothesis is derived from observations and is tested through empirical methods, often through experimentation or survey data . Empirical hypotheses may also be assessed with statistical analyses.
For example, "Regular exercise is correlated with a lower incidence of depression," could be tested through surveys that measure exercise frequency and depression levels.
A causal hypothesis proposes that one variable causes a change in another. This type of hypothesis is often tested through controlled experiments.
For example, "Smoking causes lung cancer," assumes a direct causal relationship.
Unlike causal hypotheses, associative hypotheses suggest a relationship between variables but do not imply causation.
For instance, "People who smoke are more likely to get lung cancer," notes an association but doesn't claim that smoking causes lung cancer directly.
A relational hypothesis explores the relationship between two or more variables but doesn't specify the nature of the relationship.
For example, "There is a relationship between diet and heart health," leaves the nature of the relationship (causal, associative, etc.) open to interpretation.
A logical hypothesis is based on sound reasoning and logical principles. It's often used in theoretical research to explore abstract concepts, rather than being based on empirical data.
For example, "If all men are mortal and Socrates is a man, then Socrates is mortal," employs logical reasoning to make its point.
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In any research hypothesis, variables play a critical role. These are the elements or factors that the researcher manipulates, controls, or measures. Understanding variables is essential for crafting a clear, testable hypothesis and for the stages of research that follow, such as data collection and analysis.
In the realm of hypotheses, there are generally two types of variables to consider: independent and dependent. Independent variables are what you, as the researcher, manipulate or change in your study. It's considered the cause in the relationship you're investigating. For instance, in a study examining the impact of sleep duration on academic performance, the independent variable would be the amount of sleep participants get.
Conversely, the dependent variable is the outcome you measure to gauge the effect of your manipulation. It's the effect in the cause-and-effect relationship. The dependent variable thus refers to the main outcome of interest in your study. In the same sleep study example, the academic performance, perhaps measured by exam scores or GPA, would be the dependent variable.
Beyond these two primary types, you might also encounter control variables. These are variables that could potentially influence the outcome and are therefore kept constant to isolate the relationship between the independent and dependent variables . For example, in the sleep and academic performance study, control variables could include age, diet, or even the subject of study.
By clearly identifying and understanding the roles of these variables in your hypothesis, you set the stage for a methodologically sound research project. It helps you develop focused research questions, design appropriate experiments or observations, and carry out meaningful data analysis . It's a step that lays the groundwork for the success of your entire study.
Crafting a strong, testable hypothesis is crucial for the success of any research project. It sets the stage for everything from your study design to data collection and analysis . Below are some key considerations to keep in mind when formulating your hypothesis:
Designing your study involves multiple key phases that help ensure the rigor and validity of your research. Here we discuss these crucial components in more detail.
Starting with a comprehensive literature review is essential. This step allows you to understand the existing body of knowledge related to your hypothesis and helps you identify gaps that your research could fill. Your research should aim to contribute some novel understanding to existing literature, and your hypotheses can reflect this. A literature review also provides valuable insights into how similar research projects were executed, thereby helping you fine-tune your own approach.
Choosing the right research methods is critical. Whether it's a survey, an experiment, or observational study, the methodology should be the most appropriate for testing your hypothesis. Your choice of methods will also depend on whether your research is quantitative, qualitative, or mixed-methods. Make sure the chosen methods align well with the variables you are studying and the type of data you need.
Before diving into a full-scale study, it’s often beneficial to conduct preliminary research or a pilot study . This allows you to test your research methods on a smaller scale, refine your tools, and identify any potential issues. For instance, a pilot survey can help you determine if your questions are clear and if the survey effectively captures the data you need. This step can save you both time and resources in the long run.
Finally, planning your data analysis in advance is crucial for a successful study. Decide which statistical or analytical tools are most suited for your data type and research questions . For quantitative research, you might opt for t-tests, ANOVA, or regression analyses. For qualitative research , thematic analysis or grounded theory may be more appropriate. This phase is integral for interpreting your results and drawing meaningful conclusions in relation to your research question.
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The scientific method is the basic skill process in the world of science. Since the beginning of time humans have been curious as to why and how things happen in the world around us. The scientific method provides scientists with a well structured scientific platform to help find the answers to their questions. Using the scientific method there is no limit as to what we can investigate. The scientific method can be summarised as follows:
Ask a question about the world around you.
Do background research on your questions.
Make a hypothesis about the event that gives a sensible result. You must be able to test your hypothesis through experiment.
Design an experiment to test the hypothesis. These methods must be repeatable and follow a logical approach.
Collect data accurately and interpret the data.You must be able to take measurements, collect information, and present your data in a useful format (drawings, explanations, tables and graphs).
Draw conclusions from the results of the experiment. Your observations must be made objectively, never force the data to fit your hypothesis.
Decide whether your hypothesis explains the data collected accurately.
If the data fits your hypothesis, verify your results by repeating the experiment or getting someone else to repeat the experiment.
If your data does not fit your hypothesis perform more background research and make a new hypothesis.
Remember that in the development of both the gravitational theory and thermodynamics, scientists expanded on information from their predecessors or peers when developing their own theories. It is therefore very important to communicate findings to the public in the form of scientific publications, at conferences, in articles or TV or radio programmes. It is important to present your experimental data in a specific format, so that others can read your work, understand it, and repeat the experiment.
Aim: A brief sentence describing the purpose of the experiment.
Apparatus: A list of the apparatus.
Method: A list of the steps followed to carry out the experiment.
Results: Tables, graphs and observations about the experiment.
Discussion: What your results mean.
Conclusion: A brief sentence concluding whether or not the aim was met.
A hypothesis
A hypothesis should be specific and should relate directly to the question you are asking. For example if your question about the world was, why do rainbows form, your hypothesis could be: Rainbows form because of light shining through water droplets . After formulating a hypothesis, it needs to be tested through experiment. An incorrect prediction does not mean that you have failed. It means that the experiment has brought some new facts to light that you might not have thought of before.
In science we never 'prove' a hypothesis through a single experiment because there is a chance that you made an error somewhere along the way. What you can say is that your results SUPPORT the original hypothesis.
In the analysis of the scientific method activity:
The question may already be answered in the literature, or there may be background research that you can build upon. It is also best to make a hypothesis, prediction and an experiment with as good an understanding of the topic as possible.
A controlled variable is one which you keep constant (controlled) so that it does not have an effect between readings. The independent variable is the one you change between collecting data points, while the dependent variable is the variable that changes as a result of a change in the independent variable.
It is important to identify all the variables that you think will have an effect on your investigation.
Firstly think of all the relevant variables you can change.
Secondly think of all the variables you can measure or observe.
Thirdly choose one variable to change (independent variable) which will have an effect on the one variable you can measure or observe (dependent variable).
All the other variables you need to keep constant (fixed/controlled variable).
Identifying a problem involves thinking about the world around you and a specific part of it that you don't understand.
A hypothesis is more formal, it is a prediction about that problem based on your current understanding and background research.
A scientific theory comes from an experimentally tested and proven hypothesis. It is repeatable and current data fits the theory.
Data may fit a hypothesis in a specific instance. That does not mean that the hypothesis is generally true. It is important to repeat the experiment to make sure that the experiment was not an anomaly. Before something becomes a scientific theory it must be tested repeatedly and be repeatable by different people.
Break into groups of 3 or 4 and study the flow diagram provided, then discuss the questions that follow.
Figure 1.2: Overview of scientific method.
Once you have a problem you would like to study, why is it important to conduct background research before doing anything else?
What is the difference between a dependent, independent, and controlled variable and why is it important to identify them?
What is the difference between identifying a problem, a hypothesis, and a scientific theory?
Why is it important to repeat your experiment if the data fits the hypothesis?
When the learners design their own experiment:
An example of a question that the learner might ask would be why do rainbows form?
Before beginning an investigation background research needs to be undertaken. Background research should always be referenced.
In this example the type of background research might include the particles found in the atmosphere, the diffraction of light through water and the different wavelengths of light.
Learners must write down a statement that answers their question. This is the hypothesis and should be specific, relating directly to the question they are asking.
In this example their hypothesis might be: Rainbows form because of the diffraction of light through water droplets in the atmosphere. If light is shone through water at the right angle a rainbow will form . Their hypothesis should be testable.
The learners should identify variables that are important in their specific experiment. For example, the temperature of the water, the type of light they use, the purity of the water, the angle of the light could all be variables in their experiment.
The learners should understand the difference between independent, dependent and controlled variables and be able to identify them in their experiment.
For example, the type of light might be controlled (sunlight). The temperature could be a independent variable (perform the experiment on different days with different temperatures). With the temperature as an independent variable then the angle the light comes out at could be a dependent variable, to see if there is a link. If the temperature is made a controlled variable on that day, then the angle could be the independent variable, and the shape and size of the rainbow would be the dependent variable.
The learner must design an experiment that accurately tests their hypothesis. The experiment is the most important part of the scientific method. These are all important concepts to know when designing an experiment:
The method should be written so that a complete stranger will be able to carry out the same procedure in the exact same way and get almost identical results.
The method must be clear and precise instructions including the labelling of apparatus, giving exact measurements or quantities of chemicals or substances to be used and making sure that all the apparatus used is listed.
The method must give clear instructions about/describing how the results should be recorded (table, graph, etc.)
The method should include safety precautions where possible.
The learner should present a one page experimental write up with an aim, the apparatus necessary, the method that will be followed. An example experiment is given here. Note that this is just an example, the learners could perform their experiment on anything.
The aim of this experiment is to determine what happens when sunlight is shone through a glass of water.
A clear \(\text{500}\) \(\text{ml}\) glass, three A4 pieces of white paper, a tape measure, sticky tape, a pencil, a thermometer
At least \(\text{400}\) \(\text{ml}\) of water, sunlight.
Use the sticky tape to stick an A4 piece of a paper to a sunny wall exactly \(\text{1}\) \(\text{m}\) from the ground.
Use the sticky tape to stick an A4 piece of paper above the first one, and the last A4 piece of paper below the first one.
Fill the glass with \(\text{400}\) \(\text{ml}\) water and measure the temperature (be careful to keep the thermometer out of direct sunlight between measuring the temperatures.
Hold the glass (near the bottom) level with the bottom of the middle piece of paper in the sunlight. If a rainbow forms on the sheets of paper, mark where it forms on the paper.
Measure the temperature of the water in the glass, then move the glass upwards \(\text{5}\) \(\text{cm}\) and repeat.
Repeat step \(\text{5}\) until you reach the top of the uppermost A4 piece of paper.
Your results should be presented in the form of a table (Result? should be answered with a yes or a no depending on whether a rainbow formed):
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From this data the angle of refraction of the water can be measured, as well as what angle is required for the sunlight to create a rainbow through the water.
Recording and writing up an investigation is an integral part of the scientific method. In this activity you are required to design your own experiment. Use the information provided below, and the flow diagram in the previous experiment to help you design your experiment.
The experiment should be handed in as a \(\text{1}\) - \(\text{2}\) page report. Below are basic steps to follow when designing your own experiment.
Ask a question which you want to find an answer to.
Perform background research on your topic of choice.
Write down your hypothesis.
Identify variables important to your investigation: those that are relevant, those you can measure or observe.
Decide on the independent and dependent variables in your experiment, and those variables that must be kept constant.
Design the experiment you will use to test your hypothesis:
Before you perform an experiment you should be comfortable with certain apparatus that you will be using. The following pages give some commonly used apparatus and how to use them.
Figure 1.3: The end of a ruler.
Most rulers you find have two sets of lines on them. You can ignore those with the numbers spaced further apart. We only work in the metric system and those are for the imperial system. The closest together lines are for millimetres, the thicker lines are for \(\text{5}\) \(\text{mm}\) and the thicker, longer lines with numbers next to them mark off every \(\text{10}\) \(\text{mm}\) (\(\text{1}\) \(\text{cm}\)).
Figure 1.4: Reading a thermometer.
A thermometer can have one, or two sets of numbers on it. If it has two sets of numbers one will be in Celsius, and one will be in Fahrenheit. We use Celsius, so you can ignore the side with a larger temperature range. In Figure 1.4 you can ignore the right-hand side. Looking on the left you can see that the red line (coloured ethanol here) is next to the fourth line above \(\text{0}\) \(\text{℃}\). Each small line is \(\text{1}\) \(\text{℃}\), so the temperature is \(\text{4}\) \(\text{℃}\).
Figure 1.5: A laboratory style thermometer.
Laboratory thermometers will go to much higher temperatures than those used for measuring the temperature outside, or your body temperature. It is important to make sure that the thermometer you are using can handle the temperature you will be measuring too. If not, do not use that thermometer as you will break it. Make sure your thermometer is upright whenever you use it in an experiment, to avoid incorrect results.
Video: 27HM
Figure 1.6: A scale (also referred to as a balance).
Different scales have different functions. However, a basic function of all scales is a tare button. This zeros the balance. It is important that you zero the balance before you take any measurements. If you are weighing something on a piece of paper you should tare the balance with the piece of paper on it, and weigh the substance. Make sure you check the units that your scale is weighing in. If you want your value to be accurate to \(\text{,00}\) \(\text{g}\) then the scale must measure to that accuracy. A scale that measures in \(\text{mg}\) would be best.
A burette is used to accurately measure the volume of a liquid added in an experiment. The valve at the bottom allows the liquid to be added drop-by-drop, and the initial and final volume can be measured so that the total volume added is known. More information about burettes is given to you in your first titration experiment this year in Chapter 9.
Figure 1.7: The meniscus of water in a burette.
The surface of the water (the meniscus ) is slightly higher at the edges of a container than in the middle. This is due to surface tension and the interaction between the water and the edge of the container ( Figure 1.7 ). When measuring the volume in a burette (or measuring cylinder or pipette) you should look at the bottom of the meniscus. Where that lies is where you measure the volume. So in this example the meniscus is on the fifth line below the large line that represents \(\text{1}\) \(\text{ml}\). Therefore the volume is \(\text{1,5}\) \(\text{ml}\).
It is also possible that the liquid being measured has greater internal forces than those between it and the container. Then the meniscus would be higher in the middle than at the sides, and you would use the top of the meniscus to measure your volume.
Figure 1.8: A measuring cylinder with water.
A measuring cylinder is used to measure volumes that you want accurate to the nearest millilitre or so. It is not a highly accurate way of measuring volumes. The volume in a measuring cylinder is measured in the same way as for a burette, the difference is that in a measuring cylinder the smallest volume would be at the bottom, while the largest would be at the top.
Figure 1.9: A \(\text{20}\) \(\text{ml}\) volumetric pipette.
Figure 1.10: A graduated pipette.
There are two types of pipettes you might encounter this year. A volumetric pipette has a large bulb, marked with the set volume it can measure. Above the bulb on these pipettes there is a line. For a \(\text{5}\) \(\text{ml}\) volumetric pipette, when the meniscus of your liquid sits on the line, then the volume in that pipette is \(\text{5}\) \(\text{ml}\).
A graduated pipette has the same type of marking you see on a burette. The top is \(\text{0}\) \(\text{ml}\), and the volume increases as you move down the pipette. In this pipette you should fill the pipette to near the \(\text{0}\) \(\text{ml}\) line and make a note of the volume. You can then add the desired volume, stopping when the volume in the pipette has decreased by the required amount.
A learner wondered whether the rate of evaporation of a substance was related to the boiling point of the substance. Having done background research they realised that the boiling point of a substance is linked to the intermolecular forces within the substance. They know that greater intermolecular forces require more energy to overcome. This led them to form the following hypothesis:
The larger the intermolecular forces of a substance the higher the boiling point. Therefore, if a substance has higher boiling point it will have a slower rate of evaporation.
Perform the following experiment that the learner designed to test that hypothesis.
The boiling points and rate of evaporation experiment is a very simple one meant to introduce the learners to the concept of the scientific method in a practical way. It has been broken up into three parts: performing the practical investigation, analysis of results, drawing conclusions.
The learners should be as accurated as possible when measuring the drop in volume as they will be required to plot a graph of their data.
To determine whether the rate of evaporation of a substance is related to its boiling point.
You will need the following items for this experiment:
\(\text{220}\) \(\text{ml}\) water, \(\text{20}\) \(\text{ml}\) methylated spirits, \(\text{20}\) \(\text{ml}\) nail polish remover, \(\text{20}\) \(\text{ml}\) water, \(\text{20}\) \(\text{ml}\) ethanol
One \(\text{250}\) \(\text{ml}\) beaker, four \(\text{20}\) \(\text{ml}\) beakers, a thermometer, a stopwatch or clock
All alcohols are toxic, methanol is particularly toxic and can cause blindness, coma or death. Handle all chemicals with care.
Place \(\text{200}\) \(\text{ml}\) of water into the \(\text{250}\) \(\text{ml}\) beaker and move the beaker to sunny spot. Place the thermometer in the water.
Label the four \(\text{20}\) \(\text{ml}\) beakers \(\text{1}\) - \(\text{4}\) . These beakers should be marked.
Place \(\text{20}\) \(\text{ml}\) methylated spirits into beaker 1, \(\text{20}\) \(\text{ml}\) nail polish remover into beaker 2, \(\text{20}\) \(\text{ml}\) water into beaker 3 and \(\text{20}\) \(\text{ml}\) ethanol into beaker 4.
Carefully move each beaker to the warm (sunny) spot.
Observe each dish every two minutes. Note the volume in the beaker each time.
Continue making observations for \(\text{20}\) \(\text{minutes}\). Record the volumes in a table.
Record your observations from doing the investigation in a table like the one below.
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| \(\text{78,5}\) | \(\text{56,5}\) | \(\text{100}\) | \(\text{78,4}\) |
| \(\text{20}\) | \(\text{20}\) | \(\text{20}\) | \(\text{20}\) |
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Are you looking for an easy way to teach the scientific method for kids? I’m sharing each step in this post, along with a free template you can print to help your kids walk through the scientific process.
Being inquisitive is in a kid’s nature. They LOVE asking questions (and come up with some of the best ones!). And although I love to answer them, as they get older I know that part of my job as a homeschool mom is to not answer each and every question for them.
Sooner or later, they need to have the tools to gather information and draw conclusions on their own , whether that happens inside science class or not. For kids, learning the scientific method steps can be a great way to build on skills that will be valuable in many areas of their lives.
An Englishman named Sir Francis Bacon helped create what we know as the scientific method. I thought it was interesting to learn, though, that there were multiple professional scientists and scholars who developed the scientific method over many years , and that many disagree on different ways to implement it. However, there are basic steps that have come to be accepted and taught as the scientific method (and that we get to explore with our kids!).
These steps to the scientific method that help us guide our research involve observing and asking questions, formulating a scientific hypothesis (or educated guess), planning and running an experiment, evaluating data and drawing conclusions.
Why is it important that we teach our kids the scientific method? Isn’t it enough to just have fun doing experiments when we want to? We learn so much from them without formally teaching all of these steps!
Well, yes – we certainly learn a ton from fun experiments! But as my kids are getting older, I am finding they are needing a little bit more structure in thinking through their thoughts, making guesses based on thoughtful observations, and drawing valid conclusions after careful study. These are all important skills to learn and practice. (And don’t worry – I created a FREE printable that will help you walk through this entire process. It’s not as scary as it sounds!) .
Here are the basic steps in the scientific method you’ll want to teach your kids:
Let’s go over each of the steps in a little bit more detail with an easy example, so you can see how you might teach it in your homeschool. You’ll then be able to use this method with any of your science experiments in your homeschool; my free printable will definitely help walk you through the steps as well , and is a great addition to your kids homeschool scientific journal.
Let’s use an easy example to walk through how the scientific method might look.
You have a couple of plants sitting on your windowsill, and your son asks the simple question about why they are sitting on the ledge. He wonders how the amount of light affects how a plant grows, and if it will grow without light.
And so begins the process of scientific investigation!
The first step for your kids is to take note of what questions they have, or what problems they might want to solve. What is something they are unsure about? Have them brainstorm some ideas and then do some observing and initial research to lay the groundwork for their experiment and help with the next step.
Next, they’ll form a hypothesis, or an educated guess (a guess made from good reasoning and observing!), about what they think will happen. Before they do so, it might be helpful to make sure the question is clarified and is written in “testable” form, which will help them be clear in their experiment.
For example, the question from above might be, “I wonder if plants can grow in the dark?” You can help guide your child in re-forming this question to make it testable by using phrasing like:
So – “How does the amount of light affect plant growth?”, or, “If I change the amount of sunlight a plant gets, will it affect it’s growth?”
Your child can then make a guess about what they think will happen, a possible answer, and begin planning on how to conduct the experiment.
Now comes the fun part – finding out if you are right or wrong! Your child gets to map out their procedure (what they will actually do, how and what they will record) and make a list of materials they will need to conduct the experiment.
An important part of this step is noting what the independent and dependent variables will be. An independent variable is something that you will change; a dependent variable is what you will measure. A good experiment will only have ONE independent variable at a time – you don’t want to change too many things at once, or it will be hard to measure what actually produced the results.
In our example, our independent variable will be the light source – we’ll put one plant in sunlight and one in a dark place. We’ll try to keep them in rooms of the same temperature, and we’ll use the same amount of soil, same amount of water, and the same number and type of seed in each cup.
The dependent variable is what we are going to measure – how much the plants grow.
This is the step where they record what is happening, what they observe, and then evaluate the results.
Drawing pictures and/or making graphs can definitely be helpful to display the data collected. Let them be creative with how they record this, but remind them that accuracy and being able to share data with others is important!
Finally, they get to make a final conclusion. Did the experiment answer your question, and was your hypothesis correct? Thinking about what they learned and other new questions that may have arose as a result of the experiment are worth noting.
In some cases, it might be worthwhile to repeat the experiment with a new hypothesis, or try it again in a slightly different way to help draw conclusions. For example, maybe we could repeat the plant experiment with a different type of plant to see if we got the same results.
Remember that learning about God’s creation and natural world through science experiments should be fun and enjoyable! Choose activities your kids will love, or let them help you decide what fun experiments to try. The skills that they will learn as they work through the scientific method will be valuable for them in years to come.
Absolutely! Even young children will love following along as you perform experiments with your older kids. Although they won’t be able to journal or record data like the bigger kids, simply walking through and talking about the series of steps is a great way to introduce them to the scientific process.
When your little ones ask a good question that might make for a simple science experiment, ask them what they think will happen! Then recruit any older siblings to join in on the fun.
You might have kids who are very scientifically-minded, and ask questions about everything! If not, sometimes coming up with a fun experiment can be a stumbling block.
Here are a few scientific questions your kids might have fun exploring, to get you rolling on the first step of practicing the scientific process for kids. These are also perfect to investigate for a science fair project at your school or homeschool co-op!
Once they get started brainstorming, your kids can probably come up with lots of ideas to explore for their own experiments!
There are a few great books you might want to check out as you introduce the scientific method steps. They are also wonderful for experiment ideas!
What is the Scientific Method? Science Book for Kids Mad Margaret Experiments with the Scientific Method (In the Science Lab) Awesome Science Experiments for Kids: 100+ Fun STEM / STEAM Projects and Why They Work Awesome Kitchen Science Experiments for Kids: 50 STEAM Projects You Can Eat! Steve Spangler’s Super-Cool Science Experiments for Kids: 50 mind-blowing STEM projects you can do at home Smithsonian 10-Minute Science Experiments: 50+ quick, easy and awesome projects for kids 101 Great Science Experiments: A Step-by-Step Guide The 101 Coolest Simple Science Experiments
My older kids are in 2nd and 3rd grade right now, and I created this printable for them (so it works well for mid-upper elementary-aged students). However, you can absolutely adapt it if you have younger students , or students who aren’t quite ready to do so much writing just yet. You can still teach the process!
This FREE printable comes with one sheet that lists out all the scientific method steps; this is perfect to print out and hang in your homeschool room to refer to. And if your kids are younger, you can verbally talk through the process while doing simple experiments with them, which will help prepare them for a more in-depth process when they get older.
There is also one-page-per-step that walks them through the scientific method, and a basic list of some fun science experiment ideas to try. I also have a one-page sheet your kids can use to write out their process, if you want a simpler, more compact template.
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I hope you have so much fun making memories with your kids learning about science and the scientific method for kids.
Drop a comment below: What has been your favorite science experiment you have done with your kids? What would they say is their favorite?
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Hello! Can the Scientific Method freebie be used with students I am teaching on Outschool? I am using a slide show to teach the steps, but it would be nice to have some resources for them to actually carry out the process. If this does not follow your copyright rules, I totally understand. Thanks for your consideration.
Thank you for asking, Christina, and I would love for you to use it! If possible, please give them the link (or send it to their parents) so they can download it for free from my website. I hope you get a lot of good use out of it!
Sara, I really enjoyed your post and will look into Science Shepherd. I’ve tried to use the “subscribe” button to access the free scientific method packet, but can’t seem to connect. I’m hoping this will suffice to subscribe to your channel. Thanks and have a blessed coming school year, Bonnie
Thank you so much Bonnie!! I was having an error on my site for downloading the packet, but I think it’s fixed. Please let me know if you still have issues downloading it!
Submitted by: charlie conway.
This is a lesson plan designed to be incorporated into a elementary or middle school general science class. Using BrainPOP and its resources, students will be introduced (or further exposed) to the steps necessary to undertake scientific experimentation leading (perhaps) to a Science Fair project. The Scientific Method is a core structure in learning about scientific inquiry, and although there are many variations of this set of procedures, they all usually have similar components. This lesson should take 45-60 minutes, with opportunities for extending the lesson further.
Preparation:.
These procedures may be modified according to the needs/resources of each teacher & class. For example, you may decide to do the quiz with pencil/paper, or do the quiz as a class.
If this lesson is an introduction to allowing students to plan and carry out their own experiments, then all that follows is naturally an extension to the lesson.
Other, shorter extensions are easy to develop as well.
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The word “hypothesis” might conjure up images of scientists in white coats, but crafting a solid hypothesis is a crucial skill for students in any field. Whether you are analyzing Shakespeare’s sonnets or conducting a science experiment, a well-defined research hypothesis sets the stage for your dissertation or thesis and fuels your investigation.
Table of Contents
Writing a hypothesis is a crucial step in the research process. A hypothesis serves as the foundation of your research paper because it guides the direction of your study and provides a clear framework for investigation. But how to write a hypothesis? This blog will help you craft one. Let’s get started.
A hypothesis is a clear and testable thesis statement or prediction that serves as the foundation of a research study. It is formulated based on existing knowledge, observations, and theoretical frameworks.
A hypothesis articulates the researcher’s expectations regarding the relationship between variables in a study.
Hypothesis Example
Students exposed to multimedia-enhanced teaching methods will demonstrate higher retention of information compared to those taught using traditional methods.
The formulation of a hypothesis is crucial for guiding the research process and providing a clear direction for data collection and analysis. A well-crafted research hypothesis not only makes the research purpose explicit but also sets the stage for drawing meaningful conclusions from the study’s findings.
There are two main types of hypotheses: the null hypothesis (H0) and the alternative hypothesis (H1 or Ha).
The null hypothesis posits that there is no significant effect or relationship, while the alternative hypothesis suggests the presence of a significant effect or relationship.
For example, in a study investigating the effect of a new drug on blood pressure, the null hypothesis might state that there is no difference in blood pressure between the control group (not receiving the drug) and the experimental group (receiving the drug). The alternative hypothesis, on the other hand, would propose that there is a significant difference in blood pressure between the two groups.
Writing a hypothesis involves a systematic process that guides your research and provides a clear and testable statement about the expected relationship between variables. Go through the MLA vs. APA guidelines before writing. Here are the steps to help you how to write a hypothesis:
Clearly define the research topic or question that you want to investigate. Ensure that your research question is specific and focused, providing a clear direction for your study.
Review existing literature related to your research topic. A thorough literature review helps you understand what is already known in the field, identify gaps, and build a foundation for formulating your hypothesis.
Identify the variables involved in your study. The independent variable is the factor you manipulate, and the dependent variable is the one you measure. Clearly define the characteristics or conditions you are studying.
Determine the expected relationship between the independent and dependent variables. Will a change in the independent variable lead to a change in the dependent variable? Specify whether you anticipate a positive, negative, or no relationship.
The null hypothesis represents the default position, suggesting that there is no significant effect or relationship between the variables you are studying. It serves as the baseline to be tested against. The null hypothesis is often denoted as H0.
The alternative hypothesis articulates the researcher’s expectation about the existence of a significant effect or relationship. It is what you aim to support with your research paper . The alternative hypothesis is denoted as H1 or Ha.
For example, if your research topic is about the effect of a new fertilizer on plant growth:
Confirm that your research hypothesis is testable and can be empirically investigated. Ensure that it is specific, providing a clear and measurable statement that can be validated or refuted through data collection and analysis.
Does caffeine consumption affect reaction time? | There is a significant difference in reaction time between individuals who consume caffeine and those who do not. | There is no significant difference in reaction time between individuals who consume caffeine and those who do not. | There is a significant difference in reaction time between individuals who consume caffeine and those who do not. |
What is the impact of exercise on weight loss? | Increased exercise leads to a greater amount of weight loss. | Increased exercise has no impact on the amount of weight loss. | Increased exercise does not lead to a greater amount of weight loss. |
Is there a correlation between study hours and exam scores? | There is a positive correlation between the number of study hours and exam scores. | There is no correlation between the number of study hours and exam scores. | There is a negative correlation between the number of study hours and exam scores. |
How does temperature affect plant growth? – | Plants grow better in higher temperatures. | There is no effect of temperature on plant growth. | Plants grow better in lower temperatures. |
Can music improve concentration during work? | Listening to music enhances concentration and productivity. | Listening to music has no effect on concentration and productivity. | Listening to music impairs concentration and productivity. |
How to write a hypothesis.
A null hypothesis is a statement suggesting no effect or relationship between variables in a research study. It serves as the default assumption, stating that any observed differences or effects are due to chance. Researchers aim to reject the null hypothesis based on statistical evidence to support their alternative hypothesis.
The p-value in a hypothesis test represents the probability of obtaining observed results, or more extreme ones, if the null hypothesis is true. A lower p-value suggests stronger evidence against the null hypothesis, often leading to its rejection. Common significance thresholds include 0.05 or 0.01.
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Hypothesis Definition, Format, Examples, and Tips
Verywell / Alex Dos Diaz
Falsifiability of a hypothesis.
Hypotheses examples.
A hypothesis is a tentative statement about the relationship between two or more variables. It is a specific, testable prediction about what you expect to happen in a study. It is a preliminary answer to your question that helps guide the research process.
Consider a study designed to examine the relationship between sleep deprivation and test performance. The hypothesis might be: "This study is designed to assess the hypothesis that sleep-deprived people will perform worse on a test than individuals who are not sleep-deprived."
A hypothesis is crucial to scientific research because it offers a clear direction for what the researchers are looking to find. This allows them to design experiments to test their predictions and add to our scientific knowledge about the world. This article explores how a hypothesis is used in psychology research, how to write a good hypothesis, and the different types of hypotheses you might use.
In the scientific method , whether it involves research in psychology, biology, or some other area, a hypothesis represents what the researchers think will happen in an experiment. The scientific method involves the following steps:
The hypothesis is a prediction, but it involves more than a guess. Most of the time, the hypothesis begins with a question which is then explored through background research. At this point, researchers then begin to develop a testable hypothesis.
Unless you are creating an exploratory study, your hypothesis should always explain what you expect to happen.
In a study exploring the effects of a particular drug, the hypothesis might be that researchers expect the drug to have some type of effect on the symptoms of a specific illness. In psychology, the hypothesis might focus on how a certain aspect of the environment might influence a particular behavior.
Remember, a hypothesis does not have to be correct. While the hypothesis predicts what the researchers expect to see, the goal of the research is to determine whether this guess is right or wrong. When conducting an experiment, researchers might explore numerous factors to determine which ones might contribute to the ultimate outcome.
In many cases, researchers may find that the results of an experiment do not support the original hypothesis. When writing up these results, the researchers might suggest other options that should be explored in future studies.
In many cases, researchers might draw a hypothesis from a specific theory or build on previous research. For example, prior research has shown that stress can impact the immune system. So a researcher might hypothesize: "People with high-stress levels will be more likely to contract a common cold after being exposed to the virus than people who have low-stress levels."
In other instances, researchers might look at commonly held beliefs or folk wisdom. "Birds of a feather flock together" is one example of folk adage that a psychologist might try to investigate. The researcher might pose a specific hypothesis that "People tend to select romantic partners who are similar to them in interests and educational level."
So how do you write a good hypothesis? When trying to come up with a hypothesis for your research or experiments, ask yourself the following questions:
Before you come up with a specific hypothesis, spend some time doing background research. Once you have completed a literature review, start thinking about potential questions you still have. Pay attention to the discussion section in the journal articles you read . Many authors will suggest questions that still need to be explored.
To form a hypothesis, you should take these steps:
In the scientific method , falsifiability is an important part of any valid hypothesis. In order to test a claim scientifically, it must be possible that the claim could be proven false.
Students sometimes confuse the idea of falsifiability with the idea that it means that something is false, which is not the case. What falsifiability means is that if something was false, then it is possible to demonstrate that it is false.
One of the hallmarks of pseudoscience is that it makes claims that cannot be refuted or proven false.
A variable is a factor or element that can be changed and manipulated in ways that are observable and measurable. However, the researcher must also define how the variable will be manipulated and measured in the study.
Operational definitions are specific definitions for all relevant factors in a study. This process helps make vague or ambiguous concepts detailed and measurable.
For example, a researcher might operationally define the variable " test anxiety " as the results of a self-report measure of anxiety experienced during an exam. A "study habits" variable might be defined by the amount of studying that actually occurs as measured by time.
These precise descriptions are important because many things can be measured in various ways. Clearly defining these variables and how they are measured helps ensure that other researchers can replicate your results.
One of the basic principles of any type of scientific research is that the results must be replicable.
Replication means repeating an experiment in the same way to produce the same results. By clearly detailing the specifics of how the variables were measured and manipulated, other researchers can better understand the results and repeat the study if needed.
Some variables are more difficult than others to define. For example, how would you operationally define a variable such as aggression ? For obvious ethical reasons, researchers cannot create a situation in which a person behaves aggressively toward others.
To measure this variable, the researcher must devise a measurement that assesses aggressive behavior without harming others. The researcher might utilize a simulated task to measure aggressiveness in this situation.
The hypothesis you use will depend on what you are investigating and hoping to find. Some of the main types of hypotheses that you might use include:
A hypothesis often follows a basic format of "If {this happens} then {this will happen}." One way to structure your hypothesis is to describe what will happen to the dependent variable if you change the independent variable .
The basic format might be: "If {these changes are made to a certain independent variable}, then we will observe {a change in a specific dependent variable}."
Once a researcher has formed a testable hypothesis, the next step is to select a research design and start collecting data. The research method depends largely on exactly what they are studying. There are two basic types of research methods: descriptive research and experimental research.
Descriptive research such as case studies , naturalistic observations , and surveys are often used when conducting an experiment is difficult or impossible. These methods are best used to describe different aspects of a behavior or psychological phenomenon.
Once a researcher has collected data using descriptive methods, a correlational study can examine how the variables are related. This research method might be used to investigate a hypothesis that is difficult to test experimentally.
Experimental methods are used to demonstrate causal relationships between variables. In an experiment, the researcher systematically manipulates a variable of interest (known as the independent variable) and measures the effect on another variable (known as the dependent variable).
Unlike correlational studies, which can only be used to determine if there is a relationship between two variables, experimental methods can be used to determine the actual nature of the relationship—whether changes in one variable actually cause another to change.
The hypothesis is a critical part of any scientific exploration. It represents what researchers expect to find in a study or experiment. In situations where the hypothesis is unsupported by the research, the research still has value. Such research helps us better understand how different aspects of the natural world relate to one another. It also helps us develop new hypotheses that can then be tested in the future.
Thompson WH, Skau S. On the scope of scientific hypotheses . R Soc Open Sci . 2023;10(8):230607. doi:10.1098/rsos.230607
Taran S, Adhikari NKJ, Fan E. Falsifiability in medicine: what clinicians can learn from Karl Popper [published correction appears in Intensive Care Med. 2021 Jun 17;:]. Intensive Care Med . 2021;47(9):1054-1056. doi:10.1007/s00134-021-06432-z
Eyler AA. Research Methods for Public Health . 1st ed. Springer Publishing Company; 2020. doi:10.1891/9780826182067.0004
Nosek BA, Errington TM. What is replication ? PLoS Biol . 2020;18(3):e3000691. doi:10.1371/journal.pbio.3000691
Aggarwal R, Ranganathan P. Study designs: Part 2 - Descriptive studies . Perspect Clin Res . 2019;10(1):34-36. doi:10.4103/picr.PICR_154_18
Nevid J. Psychology: Concepts and Applications. Wadworth, 2013.
By Kendra Cherry, MSEd Kendra Cherry, MS, is a psychosocial rehabilitation specialist, psychology educator, and author of the "Everything Psychology Book."
Formative Assessment Probe
By Page Keeley
Uncovering Student Ideas in Science, Volume 3: Another 25 Formative Assessment Probes
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This is the new updated edition of the first book in the bestselling Uncovering Student Ideas in Science series. Like the first edition of volume 1, this book helps pinpoint what your students know (or think they know) so you can monitor their learning and adjust your teaching accordingly. Loaded with classroom-friendly features you can use immediately, the book includes 25 “probes”—brief, easily administered formative assessments designed to understand your students’ thinking about 60 core science concepts.
Access this probe as a Google form: English
Download this probe as an editable PDF: English
The purpose of this assessment probe is to elicit students’ ideas about hypotheses. The probe is designed to find out if students understand what a hypothesis is, when it is used, and how it is developed.
Justified List
hypothesis, nature of science, scientific inquiry, scientific method
The best choices are A, B, G, K, L, and M. However, other possible answers open up discussions to contrast with the provided definition. A hypothesis is a tentative explanation that can be tested and is based on observation and/or scientific knowledge such as that that has been gained from doing background research. Hypotheses are used to investigate a scientific question. Hypotheses can be tested through experimentation or further observation, but contrary to how some students are taught to use the “scientific method,” hypotheses are not proved true or correct. Students will often state their conclusions as “My hypothesis is correct because my data prove…,” thereby equating positive results with proof (McLaughlin 2006, p. 61). In essence, experimentation as well as other means of scientific investigation never prove a hypothesis—the hypothesis gains credibility from the evidence obtained from data that support it. Data either support or negate a hypothesis but never prove something to be 100% true or correct.
Hypotheses are often confused with questions. A hypothesis is not framed as a question but rather provides a tentative explanation in response to the scientific question that leads the investigation. Sometimes the word hypothesis is oversimplified by being defined as “an educated guess.” This terminology fails to convey the explanatory or predictive nature of scientific hypotheses and omits what is most important about hypotheses: their purpose. Hypotheses are developed to explain observations, such as notable patterns in nature; predict the outcome of an experiment based on observations or prior scientific knowledge; and guide the investigator in seeking and paying attention to the right data. Calling a hypothesis a “guess” undermines the explanation that underscores a hypothesis.
Predictions and hypotheses are not the same. A hypothesis, which is a tentative explanation, can lead to a prediction. Predictions forecast the outcome of an experiment but do not include an explanation. Predictions often use if-then statements, just as hypotheses do, but this does not make a prediction a hypothesis. For example, a prediction might take the form of, “If I do [X], then [Y] will happen.” The prediction describes the outcome but it does not provide an explanation of why that outcome might result or describe any relationship between variables.
Sometimes the words hypothesis , theory , and law are inaccurately portrayed in science textbooks as a hierarchy of scientific knowledge, with the hypothesis being the first step on the way to becoming a theory and then a law. These concepts do not form a sequence for the development of scientific knowledge because each represents a different type of knowledge.
Not every investigation requires a hypothesis. Some types of investigations do not lend themselves to hypothesis testing through experimentation. A good deal of science is observational and descriptive—the study of biodiversity, for example, usually involves looking at a wide variety of specimens and maybe sketching and recording their unique characteristics. A biologist studying biodiversity might wonder, “What types of birds are found on island X?” The biologist would observe sightings of birds and perhaps sketch them and record their bird calls but would not be guided by a specific hypothesis. Many of the great discoveries in science did not begin with a hypothesis in mind. For example, Charles Darwin did not begin his observations of species in the Galapagos with a hypothesis in mind.
Contrary to the way hypotheses are often stated by students as an unimaginative response to a question posed at the beginning of an experiment, particularly those of the “cookbook” type, the generation of hypotheses by scientists is actually a creative and imaginative process, combined with the logic of scientific thought. “The process of formulating and testing hypotheses is one of the core activities of scientists. To be useful, a hypothesis should suggest what evidence would support it and what evidence would refute it. A hypothesis that cannot in principle be put to the test of evidence may be interesting, but it is not likely to be scientifically useful” (AAAS 1988, p. 5).
Elementary Students
In the elementary school grades, students typically engage in inquiry to begin to construct an understanding of the natural world. Their inquiries are initiated by a question. If students have a great deal of knowledge or have made prior observations, they might propose a hypothesis; in most cases, however, their knowledge and observations are too incomplete for them to hypothesize. If elementary school students are required to develop a hypothesis, it is often just a guess, which does little to contribute to an understanding of the purpose of a hypothesis. At this grade level, it is usually sufficient for students to focus on their questions, instead of hypotheses (Pine 1999).
Middle School Students
At the middle school level, students develop an understanding of what a hypothesis is and when one is used. The notion of a testable hypothesis through experimentation that involves variables is introduced and practiced at this grade level. However, there is a danger that students will think every investigation must include a hypothesis. Hypothesizing as a skill is important to develop at this grade level but it is also important to develop the understandings of what a hypothesis is and why and how it is developed.
High School Students
At this level, students have acquired more scientific knowledge and experiences and so are able to propose tentative explanations. They can formulate a testable hypothesis and demonstrate the logical connections between the scientific concepts guiding a hypothesis and the design of an experiment (NRC 1996).
This probe is best used as is at the middle school and high school levels, particularly if students have been previously exposed to the word hypothesis or its use. Remove any answer choices students might not be familiar with. For example, if they have not encountered if-then reasoning, eliminate this distracter. The probe can also be modified as a simpler version for students in grades 3–5 by leaving out some of the choices and simplifying the descriptions.
K–4 Understandings About Scientific Inquiry
5–8 Understandings About Scientific Inquiry
5–8 Science as a Human Endeavor
9–12 Abilities Necessary to Do Scientific Inquiry
9–12 Understandings About Scientific Inquiry
*Indicates a strong match between the ideas elicited by the probe and a national standard’s learning goal.
K–2 Scientific Inquiry
3–5 Scientific Inquiry
6–8 Scientific Inquiry
6–8 Values and Attitudes
9–12 Scientific Inquiry
American Association for the Advancement of Science (AAAS). 1993. Benchmarks for science literacy. New York: Oxford University Press.
Keeley, P. 2005. Science curriculum topic study: Bridging the gap between standards and practice. Thousand Oaks, CA: Corwin Press.
McLaughlin, J. 2006. A gentle reminder that a hypothesis is never proven correct, nor is a theory ever proven true. Journal of College Science Teaching 36 (1): 60–62.
National Research Council (NRC). 1996. National science education standards. Washington, DC: National Academy Press.
Schwartz, R. 2007. What’s in a word? How word choice can develop (mis)conceptions about the nature of science. Science Scope 31 (2): 42–47.
VanDorn, K., M. Mavita, L. Montes, B. Ackerson, and M. Rockley. 2004. Hypothesis-based learning. Science Scope 27: 24–25.
American Association for the Advancement of Science (AAAS). 1988. Science for all Americans. New York: Oxford University Press.
Driver, R., J. Leach, R. Millar, and P. Scott. 1996. Young people’s images of science. Buckingham, UK: Open University Press.
Pine, J. 1999. To hypothesize or not to hypothesize. In Foundations: A monograph for professionals in science, mathematics, and technology education. Vol. 2. Inquiry: Thoughts, views, and strategies for the K–5 classroom. Arlington, VA: National Science Foundation.
Reports Article
Frequently, when we hear the word ‘hypothesis’, we immediately think of an investigation in the form of a science experiment. This is not surprising, as science is the subject area where we are usually first introduced to the term.
However, the term hypothesis also applies to investigations and research in many diverse areas and branches of learning, leaving us wondering how to write a hypothesis in statistics and how to write a hypothesis in sociology alongside how to write a hypothesis in a lab report.
We can find hypotheses at work in areas as wide-ranging as history, psychology, technology, engineering, literature, design, and economics. With such a vast array of uses, hypothesis writing is an essential skill for our students to develop.
A hypothesis is a proposed or predicted answer to a question. The purpose of writing a hypothesis is to follow it up by testing that answer. This test can take the form of an investigation, experiment, or writing a research paper that will ideally prove or disprove the hypothesis’s prediction.
Despite this element of the unknown, a hypothesis is not the same thing as a guess. Though the hypothesis writer typically has some uncertainty, the creation of the hypothesis is generally based on some background knowledge and research of the topic. The writer believes in the likelihood of a specific outcome, but further investigation will be required to validate or falsify the claim made in their hypothesis.
In this regard, a hypothesis is more along the lines of an ‘educated guess’ that has been based on observation and/or background knowledge.
A hypothesis should:
This HUGE BUNDLE offers 97 PAGES of hands-on, printable, and digital media resources. Your students will be WRITING procedures with STRUCTURE, INSIGHT AND KNOWLEDGE like never before.
If students listen to classical music while studying, they will retain more information.
Mold growth is affected by the level of moisture in the air.
Students who sleep for longer at night retain more information at school.
Employees who work more than 40 hours per week show higher instances of clinical depression.
Time spent on social media is negatively correlated to the length of the average attention span.
People who spend time exercising regularly are less likely to develop a cardiovascular illness.
If people are shorter, then they are more likely to live longer.
Variables are an essential aspect of any hypothesis. But what exactly do we mean by this term?
Variables are changeable factors or characteristics that may affect the outcome of an investigation. Things like age, weight, the height of participants, length of time, the difficulty of reading material, etc., could all be considered variables.
Usually, an investigation or experiment will focus on how different variables affect each other. So, it is vital to define the variables clearly if you are to measure the effect they have on each other accurately.
There are three main types of variables to consider in a hypothesis. These are:
The Independent Variable
The independent variable is unaffected by any of the other variables in the hypothesis. We can think of the independent variable as the assumed cause .
The Dependent Variable
The dependent variable is affected by the other variables in the hypothesis. It is what is being tested or measured. We can think of the dependent variable as the assumed effect .
For example, let’s investigate the correlation between test scores across different age groups. The age groups will be the independent variable, and the test scores will be the dependent variable .
Now that we know what variables are let’s look at how they work in the various types of hypotheses.
There are many different types of hypotheses, and it is helpful to know the most common of these if the student selects the most suitable tool for their specific job.
The most frequently used types of hypotheses are:
The complex hypothesis, the empirical hypothesis, the null hypothesis, the directional hypothesis, the non-directional hypothesis.
This straightforward hypothesis type predicts the relationship between an independent and dependent variable.
Example: Eating too much sugar causes weight gain.
This type of hypothesis is based on the relationship between multiple independent and/or dependent variables.
Example: Overeating sugar causes weight gain and poor cardiovascular health.
Also called a working hypothesis, an empirical hypothesis is tested through observation and experimentation. An empirical hypothesis is produced through investigation and trial and error. As a result, the empirical hypothesis may change its independent variables in the process.
Example: Exposure to sunlight helps lettuces grow faster.
This hypothesis states that there is no significant or meaningful relationship between specific variables.
Example: Exposure to sunlight does not affect the rate of a plant’s growth.
This type of hypothesis predicts the direction of an effect between variables, i.e., positive or negative.
Example: A high-quality education will result in a greater number of career opportunities.
Similar to the directional hypothesis, this type of hypothesis predicts the nature of the effect but not the direction that effect will go in.
Example: A high-quality education will affect the number of available career opportunities.
The starting point for any hypothesis is asking a question. This is often called the research question . The research question is the student’s jumping-off point to developing their hypothesis. This question should be specific and answerable. The hypothesis will be the point where the research question is transformed into a declarative statement.
Ideally, the questions the students develop should be relational, i.e., they should look at how two or more variables relate to each other as described above. For example, what effect does sunlight have on the growth rate of lettuce?
The research is an essential part of the process of developing a hypothesis. Students will need to examine the ideas and studies that are out there on the topic already. By examining the literature already out there on their topic, they can begin to refine their questions on the subject and begin to form predictions based on their studies.
Remember, a hypothesis can be defined as an ‘educated’ guess. This is the part of the process where the student educates themself on the subject before making their ‘guess.’
By now, your students should be ready to form their preliminary hypotheses. To do this, they should first focus on defining their independent and dependent variables. Now may be an excellent opportunity to remind students that the independent variables are the only variables that they have complete control over, while dependent variables are what is tested or measured.
With variables defined, students can now work on a draft of their hypothesis. To do this, they can begin by examining their variables and the available data and then making a statement about the relationship between these variables. Students must brainstorm and reflect on what they expect to happen in their investigation before making a prediction upon which to base their hypothesis. It’s worth noting, too, that hypotheses are typically, though not exclusively, written in the present tense.
Students revisit the different types of hypotheses described earlier in this article. Students select three types of hypotheses and frame their preliminary hypotheses according to each criteria. Which works best? Which type is the least suitable for the student’s hypothesis?
By now, students will have made a decision on which type of hypothesis suits their needs best, and it will now be time to finalize the wording of their hypotheses. There are various ways that students can choose to frame their hypothesis, but below, we will examine the three most common ways.
The If/Then Phrasing
This is the most common type of hypothesis and perhaps the easiest to write for students. It follows a simple ‘ If x, then y ’ formula that makes a prediction that forms the basis of a subsequent investigation.
If I eat more calories, then I will gain weight.
Correlation Phrasing
Another way to phrase a hypothesis is to focus on the correlation between the variables. This typically takes the form of a statement that defines that relationship positively or negatively.
The more calories that are eaten beyond the daily recommended requirements, the greater the weight gain will be.
Comparison Phrasing
This form of phrasing is applicable when comparing two groups and focuses on the differences that the investigation is expected to reveal between those two groups.
Those who eat more calories will gain more weight than those who eat fewer calories.
Questions to ask during this process include:
If the purpose of a hypothesis is to provide a reason to pursue an investigation, then the student will need to gather related information together to fuel that investigation.
While, by definition, a hypothesis leans towards a specific outcome, the student shouldn’t worry if their investigations or experiments ultimately disprove their hypothesis. The hypothesis is the starting point; the destination is not preordained. This is the very essence of the scientific method. Students should trust the results of their investigation to speak for themselves. Either way, the outcome is valuable information.
When teaching young scientists and writers, it’s essential to remember that the process of formulating a hypothesis is not always straightforward. It’s easy to make mistakes along the way, but with a bit of guidance, you can ensure your students avoid some of the most common pitfalls like these.
Hypothesis Warmup Activity: First, organize students into small working groups of four or five. Then, set each group to collect a list of hypotheses. They can find these by searching on the Internet or finding examples in textbooks . When students have gathered together a suitable list of hypotheses, have them identify the independent and dependent variables in each case. They can underline each of these in different colors.
It may be helpful for students to examine each hypothesis to identify the ‘cause’ elements and the ‘effect’ elements. When students have finished, they can present their findings to the class.
Task 1: Set your students the task of coming up with an investigation-worthy question on a topic that interests them. This activity works particularly well for groups.
Task 2: Students search for existing information and theories on their topic on the Internet or in the library. They should take notes where necessary and begin to form an assumption or prediction based on their reading and research that they can investigate further.
Task 3: When working with a talking partner, can students identify which of their partner’s independent and dependent variables? If not, then one partner will need to revisit the definitions for the two types of variables as outlined earlier.
Task 4: Organize students into smaller groups and task them with presenting their hypotheses to each other. Students can then provide feedback before the final wording of each hypothesis is finalized.
Perhaps due to their short length, learning how to create a well-written hypothesis is not typically afforded much time in the curriculum.
However, though they are brief in length, they are complex enough to warrant focused learning and practice in class, particularly given their importance across many curriculum areas.
Learning how to write a hypothesis works well as a standalone writing skill. It can also form part of a more comprehensive academic or scientific writing study that focuses on how to write a research question, develop a theory, etc.
As with any text type, practice improves performance. By following the processes outlined above, students will be well on their way to writing their own hypotheses competently in no time.
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First-year students who attended most lectures will have better exam scores than those who attended few lectures. 6. Write a null hypothesis. If your research involves statistical hypothesis testing, you will also have to write a null hypothesis. The null hypothesis is the default position that there is no association between the variables.
This investigation will show the learners that increasing the number of resistors in parallel to each other, causes the overall resistance of the circuit to decrease and the current strength to increase. ... HYPOTHESIS: Write a hypothesis for this investigation. This is a learner-dependent answer. Learners need to identify the independent and ...
How to Write a Good Hypothesis. Writing a good hypothesis is definitely a good skill to have in scientific research. But it is also one that you can definitely learn with some practice if you don't already have it. Just keep in mind that the hypothesis is what sets the stage for the entire investigation. It guides the methods and analysis.
Step 5: Phrase your hypothesis in three ways. To identify the variables, you can write a simple prediction in if … then form. The first part of the sentence states the independent variable and the second part states the dependent variable. If a first-year student starts attending more lectures, then their exam scores will improve.
How to use the resource. This could be used to follow on from a class investigation into the effect of beaker size on the length of time the candle burnt. The slides can be used to guide a class discussion, in combination with or as an alternative to the worksheets. Give learners time to read the concept cartoon and consider their own ideas ...
At the core of biology and other sciences lies a problem-solving approach called the scientific method. The scientific method has five basic steps, plus one feedback step: Make an observation. Ask a question. Form a hypothesis, or testable explanation. Make a prediction based on the hypothesis. Test the prediction.
The Scientific Method starts with aquestion, and background research is conducted to try to answer that question. If you want to find evidence for an answer or an answer itself then you construct a hypothesis and test that hypothesis in an experiment. If the experiment works and the data is analyzed you can either prove or disprove your hypothesis.
Use simple language: While your hypothesis should be conceptually sound, it doesn't have to be complicated. Aim for clarity and simplicity in your wording. State direction, if applicable: If your hypothesis involves a directional outcome (e.g., "increase" or "decrease"), make sure to specify this.
It's essentially an educated guess—based on observations—of what the results of your experiment or research will be. Some hypothesis examples include: If I water plants daily they will grow faster. Adults can more accurately guess the temperature than children can. Butterflies prefer white flowers to orange ones.
Learners must write down a statement that answers their question. This is the hypothesis and should be specific, relating directly to the question they are asking. ... Recording and writing up an investigation is an integral part of the scientific method. In this activity you are required to design your own experiment. ... Write down your ...
Steps of the Scientific Method for Kids. Here are the basic steps in the scientific method you'll want to teach your kids: Observe and ask a question. Form a hypothesis. Do an experiment. Evaluate your data. Draw a conclusion. Let's go over each of the steps in a little bit more detail with an easy example, so you can see how you might ...
This lesson is designed to guide your students through the steps of the scientific method (Figure 1) using a fun, hands-on project: paper rockets. You can read about the scientific method in much more detail in this guide. Image Credit: created by Amy Cowen for Science Buddies / Science Buddies. Figure 1. Steps of the scientific method.
Students will: Students will use BrainPOP features to build their understandings of the Scientific Method. Students will learn how to identify and write effective hypotheses. Students will use game play to write an appropriate hypothesis for an experiment. Students will identify and utilize the tools necessary to design a scientific investigation.
Identify the variables involved. Formulate a clear and testable prediction. Use specific and measurable terms. Align the hypothesis with the research question. Distinguish between the null hypothesis (no effect) and alternative hypothesis (expected effect). Ensure the hypothesis is falsifiable and subject to empirical testing.
hypothesis, e.g. Students' high scores on the community scale will be highly related to good grades in the distance education course. A hypothesis is an educated guess, and it can be supported or refuted through experimentation or observation. If the hypothesis is supported, evidence exists that supports the theory. If the
A hypothesis is a tentative statement about the relationship between two or more variables. It is a specific, testable prediction about what you expect to happen in a study. It is a preliminary answer to your question that helps guide the research process. Consider a study designed to examine the relationship between sleep deprivation and test ...
How to write a hypothesis: Two variables (dependent and independent) should be mentioned in the hypothesis. A hypothesis should show the relationship between variables and a hypothesis is NOT a question. The hypothesis must be measureable. The hypothesis: 1. Indicates what you expect the outcome of the investigation to be. 2.
Use caution when asking students to write lab reports that use the same format regardless of the type of investigation conducted. The format used in writing about an investigation may imply a rigid, fixed process or erroneously misrepresent aspects of science, such as that hypotheses are developed for every scientific investigation.
How to Write a Hypothesis: A STEP-BY-STEP GUIDE. Ask a Question. The starting point for any hypothesis is asking a question. This is often called the research question. The research question is the student's jumping-off point to developing their hypothesis. This question should be specific and answerable.
Task: Write a hypothesis for each of the following investigation on the answer sheet. Investigation 1 "Sarah took ten identical iron nails and place them in a container. She painted half of the nails and left the rest unpainted. She then put the container of nails outside for a month. She recorded that the unpainted nails started to rust within ...
Steps to Writing Your Hypothesis. 1. Identify Your Research Question. Your research question is the starting point for developing your hypothesis. A good research question should be clear, focused, and researchable. It often stems from a literature review where gaps in existing research are identified.
In this lesson, students will become familiar with the steps for writing a scientific hypothesis. Process Begin the lesson by asking students to define the word hypothesis. Have students share their definitions. Share with students that one of the most important skills a scientist has is the ability to write a good hypothesis.