experiments drop of water

July 2, 2015

The Magnifying Effect of a Water Drop

An optical science activity from Science Buddies

By Science Buddies

Can a droplet of water change what you can spy with your little eye? Learn about optics and lenses in this larger-than-life science activity!

George Retseck

Key concepts Lens Magnifying glass Optics Light

Introduction Have you ever studied an everyday object through a magnifying glass—and been amazed at what you could see? Or have you ever noticed, for example in a swimming pool, that an object that is sticking out of the water looks different just above and just below the surface? In this activity you will learn a little bit more about both of these observations. Get ready to bend light, magnify letters and have fun with water drops—all while getting a glimpse into how lenses work!

Lenses are the key components in eyeglasses, contact lenses, binoculars and telescopes—just to name a few devices. With this activity a homemade magnifying glass is only a drop away!

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Background You see an object because light rays reflected from the object shine into your eye, creating an image on the retina inside your eye. Signals to your brain allow it to re-create the picture of the object.

A light ray bouncing off an object usually travels in a straight line to your eye. Things change when a transparent material, such as glass or water, gets in the way. When a light ray traveling through air enters such a material, it changes direction, creating a sort of kink. Another kink is introduced when the ray leaves the material. Therefore, the final image of the object in your eye might be different due to the changes in direction of the light on its way to your eye. Your brain is unaware of these kinks and expects an image created by rays that traveled in a straight line. As a result, it might reconstruct a picture that is different from the initial object. Your eyes and brain might have been fooled!

Lenses use these kinks to make objects look bigger or smaller, closer or farther away. A convex lens bends light rays inward, which results in the object being perceived as larger or closer. A concave lens bends rays outward; you get the perception that objects are smaller or farther away. There is no overall bending of light for a flat lens. You perceive the object as it is.

Now that you know a little about light and lenses, are you ready to let your eyes and brain be fooled?

A newspaper page

Two rulers with metric measurements on them, preferably with dark markings

One transparency film or clear sheet protector

Drinking glass with water

Medicine dropper (optional)

Mobile device with a camera (optional)

Small transparent plastic cup or tiny tasting cup with a flat bottom (optional)

Preparation

Find a waterproof work area.

Select an article in the newspaper with a small font. You can use your ruler to measure the height of the letters; they should be a few millimeters high.

Place the transparency film on top of a newspaper page.

Create a drop of water near the middle of the transparency film. Use a water dropper or your finger to let two or three drops fall on the film and merge into one bigger drop. Examine your water drop. Is the top of the drop surface flat, curved inward or curved outward?

Shift your transparency film so the water drop lays on top of the small print letters.

Close or cover one eye and look from above with the other eye at the letters under the drop. Compare them with the letters next to but not covered by the drop. Do they look the same? Does one appear bigger or smaller than the other?

Using two hands, carefully lift and hold the transparency film about half an inch above the newspaper, leaving the newspaper on your work surface. You might need help lifting the transparency film if you like to cover one eye with a hand.

Close or cover one eye and look carefully from above through the water drop at the letters on the newspaper. Do the letters appear different than when the transparency film rested on the newspaper? What happens when you move the transparency film farther up?

Move the transparency film up and down a couple of times looking from above through the water drop with one eye. How does your perception of the letters change as you move the transparency film farther up or back down? Why do you think this happens?

To measure the magnification factor of your water drop, put a ruler under your transparency film on your work surface and another ruler next to the drop on top of the transparency film, but be sure to prevent the ruler from touching the drop.

Lift the transparency film with the top ruler and water drop about 1.3 centimeters up and do your best to measure the length of a millimeter indication of the bottom ruler, as seen through the water drop. (You might need help lifting the transparency film together with the ruler and the water drop.) How many millimeters does one millimeter indication measure? This number tells you by what factor objects appear bigger when seen through your water drop. Are you surprised about the magnification factor you obtained?

Measure the magnification factor of your water drop when you lift the transparency film higher up. Does the magnification factor change when you lift the transparency higher? Could you find ways to make the magnification factor very big?

Repeat the activity, this time using a larger water drop. What happens to the curvature of the top surface of the water drop when you increase the size of the drop? Is it more, less or similarly curved? Do bigger water drops yield a different magnification factor?

Extra: What do you think would be the optimum water drop size and its height above the newspaper to increase the readability of your chosen newspaper line? Would you choose the same conditions if you were investigating the details of an insect?

Extra: Go around the house or the garden looking at objects through your new magnification glass. What kind of surprising details can you find?

Extra: You just used water to create a magnifying glass, making objects appear larger. What do you think will happen if you look through a bigger layer of water held in a cup? To test this, find a small or tiny transparent plastic cup with a flat bottom. To verify that the cup itself does not act as a lens, place the empty cup over a straight line found in your newspaper, look through the cup and observe. Does the line appear straight? Does it appear to have the same thickness if you lift the cup? If not, find another cup, because the bottom of this cup already acts as a lens. Why do you think it is important that the cup used to test if a layer of water in a cup acts as a lens does not act as a lens already? Once you have a cup that does not act like a lens, fill it with a layer of water (about 1.3 centimeters high) and look from above through the water to the letters on your newspaper. How do the letters appear? Does their appearance change when you move the cup up and down? You might want to shift to a font with larger letters. Can you calculate the magnification factor of this lens? Note that a magnification factor smaller than 1 indicates the object appears smaller than it is. As an example, a magnification factor of one half indicates that the object appears to be half its size.

Extra: Optical instruments often use a combination of several lenses. If you made both the water-drop lens and the cup-with-water lens, observe what happens if you combine both. You can put the transparency on top of your cup and look from above or ask a helper to hold your transparency film with the water drop as you hold the cup above it. What do you think will happen? Can you measure the magnification factors for both lenses individually (at the exact distance you are holding them when you combine both) and when combined? If you do this for a couple of different distances, you might be able to develop a formula.

Extra: Would other liquids also create magnification? Would one liquid work better than another? Think of oil or vinegar or soy sauce. Which ones do you think might work, and why?

[break] Observations and results Did you see how objects appear larger when looked at through a water drop? The surface of a water drop curves outward to make a dome. This outward, or convex, curvature bends light rays inward. The result is an enlarged image on the retina of your eye. The object appears bigger than it is.

The surface of a smaller drop is even more curved, creating a bigger change in direction of the light ray. The result is a larger magnification. Changing the position of the water drop with respect to the letters and your eye will also affect the magnification factor. Due to something called the capillary effect, however, a layer of water in a cup shows a surface that is slightly bent inward. It will act as a concave lens that bends the light rays outward. As a result, letters seen through the layer of water in a cup appear smaller than they are. When you combine several lenses, the magnification factor of the set of lenses is the product of the magnification factors of the individual lenses.

Any clear liquid will work as a lens. As long as the bottom and top surfaces of the layer or drop are not parallel, the lens will change the appearance of the object. Depending on the liquid, the magnification factor of similar drops made up of different liquids will vary.

More to explore Simple Magnification , from The Florida State University A Magnifying Discovery , from Science Buddies Picture This: Building a Cell Phone Microscope , from Science Buddies Measure Surface Tension with a Penny , from Scientific American

This activity brought to you in partnership with Science Buddies

Drops on a Penny

Hydrogen bonds and surface tension give water some amazing properties. let's use them to see how many drops of water fit on a penny.

Print this Experiment

You might think that you can’t fit many drops of water on the surface of a penny. Pennies are just so small! In the Drops on a Penny experiment, though, you’ll experience surface tension and cohesion at their finest. How many drops of water can you fit? There’s only one way to find out… by adding one drop at a time!

Experiment Videos

Here's What You'll Need

Eyedropper or pipette, let's try it.

Wash and rinse a penny in tap water. Dry it completely with a paper towel.

Place the penny on a flat surface. The flatter the surface, the better this experiment is going to go.

Use an eyedropper or pipette to draw up water.

Carefully, drop individual drops of water onto the flat surface of the penny.

Keep track of the water drops as you add them, one at a time, until water runs over the edge of the penny. You’ll probably be surprised by the number of drops you get on there!

How Does It Work

There are two properties at work in this experiment: cohesion and surface tension. Cohesion is the attraction of like molecules to one another. In this case, the like molecules are the H20 molecules in the water drops. Surface tension is a special term we use to describe the cohesion between water molecules.

Water’s cohesion and surface tension are special because of hydrogen bonds. Hydrogen bonds are formed by the hydrogen atoms of one molecule being attracted to the oxygen atoms of another molecule.

The cohesion and surface tension of water becomes apparent when the drops of water you add to the penny reach the penny’s edge. Once the water has reached the edge, you begin to see a bubble or dome of water forming on top of the penny. The bubble shape is a result of the water molecules clinging to one another in an optimal shape (just like the bonds on the surface of a blown bubble).

Take It Further

Extend this experiment by trying different coins such as dimes, nickels, or quarters.

Science Fair Connection

Demonstrating the cohesive properties of water is pretty cool, but it isn’t a science fair project.  You can create a science fair project by identifying a variable, or something that changes, in this experiment.  Let’s take a look at some of the variable options that might work:

• Try testing different liquids such as vegetable oil, salt water, soda, etc. How does this change the number of drops the penny can hold?
• Try testing surfaces with different shapes. Do circular surfaces hold the same amount of water as rectangular surfaces with approximately the same surface area?

That’s just a couple of ideas, but you aren’t limited to those! Try coming up with different ideas of variables and give them a try.  Remember, you can only change one thing at a time.  If you are testing different liquids, make sure that the other factors are remaining the same.

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Drops Of Water On A Penny

Have you ever thought about how many drops of water can fit on a penny ? Try this fun science experiment with things found in your purse or pocket! Explore the surface tension of water with this fun and easy penny lab with the kids. We are always on the hunt for simple science experiments , and this one is just super fun and easy!

Explore How Many Water Drops On Penny

Add this simple penny lab to your science activities this season. If you want to learn about the surface tension of water, let’s dig in. While you’re at it, make sure to check out these other fun water science experiments.

Exploring water drops on a penny is a fantastic science experiment for kids because it’s simple and fascinating. By placing drops of water onto a penny, kids can observe how the water beads up and forms a dome-like shape, defying gravity.

This phenomenon occurs due to surface tension , the cohesive force that causes water molecules to stick together. Through this experiment, kids can learn about surface tension and how it affects the behavior of liquids. They can also experiment with variables such as the number of water drops or the penny’s cleanliness to see how it impacts the results. Additionally, this experiment can be efficiently conducted with everyday household items, making it accessible and engaging for scientists of all ages.

Water Drops On A Penny Project

You can also easily turn your penny experiment into a fantastic presentation along with your hypothesis. Check out the resources below to get started.

• Easy Science Fair Projects
• Science Project Tips From A Teacher
• Science Fair Board Ideas

Penny Lab Experiment In The Classroom

TIP: If you want to add a little variety to this experiment, swap out the pennies for nickels, dimes, and quarters. Ask your students to guess how many drops will fit on each coin. Record the date from the experiment and make a class graph chart with your results!

Additional ideas for penny lab hypotheses include using different liquids or clean vs. dirty pennies . What else can you think of when creating an experiment?

Get Your Free Printable Penny Lab Guide!

Penny Lab Experiment

Let’s investigate how many drops of water can fit on a penny. Grab your purse, turn over the couch cushions, or break out the piggy bank; it’s time to find some pennies to experiment with!

• Eyedropper or pipette
• Food coloring (makes seeing this in action MUCH easier, but is optional)
• Small bowls

Penny Experiment Set Up:

STEP 1: Add water to both of your bowls, and one of them, add green food coloring. This is optional if you want to see the drops a bit better.

STEP 2: Use an eyedropper or pipette to pick up and carefully drip one drop of water at a time onto the penny.

STEP 3: Count how many drops you can fit onto one penny until the water overflows.

We were able to get ours up to about 27! Go ahead and record the data for separate trials on the same coin. What can you conclude?

Why Do So Many Drops Of Water Fit On A Penny?

Were you surprised that a lot more drops of water fit on a penny than you predicted? We had 27 drops of water on ours!

What property of water allows the water to stick to the penny? Surface tension and cohesion are why you can get so many drops of water on a penny.

Cohesion is the “stickiness” of like molecules to one another. Water molecules love to stick together! Surface tension is the result of all the water molecules sticking together. Learn more about the surface tension of water !

Once the water has reached the edge of the penny, a dome shape begins to form. This is due to the surface tension forming a shape with the least amount of surface area possible (like bubbles )!

What happens if you use a different liquid like alcohol? Can you as many drops on a penny?

More Fun Penny Experiments

• Sink the boat challenge!
• Penny Spinners
• Green Pennies Experiment
• Paper Bridge STEM Challenge
• Lemon Battery STEM Project

Use the Scientific Method

This drops of water on a penny experiment is a fantastic opportunity to use the scientific method and record your experiment using the free mini worksheet pack below.

You can read about using the scientific method here , and find more information on the independent and dependent variables !

The first step in the scientific method is asking a question and developing a hypothesis.

Apply the scientific method to this drops-on-a-penny science activity and turn it into a surface tension experiment by choosing a question to investigate.

• How many drops do you think will fit on a penny? (PREDICTION)
• What happens when one drop of water meets another drop? (OBSERVATION)
• Which coin held the most water? (EXPLANATION)
• Can you think of everyday examples of surface tension? (APPLICATION)

Helpful Science Resources To Get You Started

Here are a few resources that will help you introduce science more effectively to your kiddos or students and feel confident yourself when presenting materials. You’ll find helpful free printables throughout.

• Best Science Practices (as it relates to the scientific method)
• Science Vocabulary
• 8 Science Books for Kids
• All About Scientists
• Science Supplies List
• Science Tools for Kids

More Science Experiments To Try

Check out our list of science experiments for Jr Scientists!

• Walking Water
• Rubber Egg Experiment
• Why Do Things Float In Salt Water?
• Water Density Experiment

Printable Science Projects For Kids

If you’re looking to grab all of our printable science projects in one convenient place plus exclusive worksheets and bonuses like a STEAM Project pack, our Science Project Pack is what you need! Over 300+ Pages!

• 90+ classic science activities  with journal pages, supply lists, set up and process, and science information.  NEW! Activity-specific observation pages!
• Best science practices posters  and our original science method process folders for extra alternatives!
• Be a Collector activities pack  introduces kids to the world of making collections through the eyes of a scientist. What will they collect first?
• Know the Words Science vocabulary pack  includes flashcards, crosswords, and word searches that illuminate keywords in the experiments!
• My science journal writing prompts  explore what it means to be a scientist!!
• Bonus STEAM Project Pack:  Art meets science with doable projects!
• Bonus Quick Grab Packs for Biology, Earth Science, Chemistry, and Physics

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Water Drop Science: 8 Explorations

Introduction: Water Drop Science: 8 Explorations

Water you waiting for? There's an ocean of knowledge and experience lying in every wee drop water, and it's now you can start checking it out. From looking at surface tension to magnifying effects to vapor cushions, the water drop makes being little seem like a pretty big deal. I love doing these explorations with my students, and each one is a take-off point for more.

Water Drop Science: 8 Explorations is a way to dive into water drops like you never have before. If you have some other water drop experiments that you love, share them in the comments. H2Okay, let's go!

Step 1: Leidenfrost Drops

A hot drop on the right surface will start to boogie. Heat up a metal spoon over a stove or any other flame, and once it is very hot, squeeze out a couple water droplets. The drops will collect and remain in a surprisingly orb-like shape and dance around the metal spoon even after you've taken it off of direct heat. Play around with the temperatures, shapes, and ways that you heat the spoon to get massively different effects. Of course, be careful when dealing with hot things!

This all happens because of something called the Leidenfrost Effect where a liquid when in contact with a surface much hotter than its boiling point, produces a vaporized layer creating a buffer between the surface and the drop. It's like a water drop hovercraft! Additionally, with special heated surfaces, you can even get water to "climb uphill" as you can see in this Leidenfrost Maze .

Step 2: Water Lenses

Drop a few water drops on to a mirror to get a fascinating lens effect looking back at you. You'll see your face in each one of the drops on the mirror. but with the image flipped upside down. These actually work like any other lens, including our own eye, where the light coming in gets refracted and projects upside-down which means our brain is doing the flipping . See how many you can fit! For more information on lenses, start with this !

Step 3: Penny Blobs (surface Tension)

See how big you can make your penny blobs before they spill over (44 drops for one of them!). Besides giving all of your pennies bulging hats, you're exploring surface tension , which is the nature of liquids to try to reduce surface area by sticking together with adhesion . You can fit a bunch of drops on the head of a penny, even beyond what you'd think!

Try the experiment out with other liquids such as milk, oil, water with salt, and water with soap, and you'll find you get different results with how many drops a penny can take. It turns out that water has a relatively high surface tension compared to other liquids, which means other liquids don't make it as long before they run off the side. Try it out, count your drops, and clean up those micro-messes after!

Step 4: Water Drop Macro Lens

With a dab of water on your phone's camera, you can suddenly create a macro lens for some up-close magnifying photography. This is kind of like the water mirror lenses, but now we can see through from the other side, and you can use this to explore quite a bit in nature. Dab a little bit of water over a phone camera, and click away to get some neat photos. Try fingerprints, leaves, and clothing to get a start on your new world of macro photography!

This is due to the convex nature of water drops, which bend light such that objects will appear larger in the camera than they truly are. Play around, and see what you can discover in your world when you look up close.

Step 5: Life in a Drop

A drop of water can be like a little world when it comes to microfauna. Drop a cup of water with weights into the ocean, a river, a lake, a pond, or a puddle, and pull it out to get a sample of the local water. Often the closer to the base sediment you get, the more it will be teeming with visible life.

After you scoop it up, drop a bit of it on a mirror, and take out your handy-dandy laser. Get in a dark area, and shine your laser through the drop of water, which will act like a projector displaying the shadows of any life that go by. I found some zooplankton! What will you find in yours?

Step 6: Accordian Snake (capillary Action)

This one is a fast-food special. Scrunch up your straw wrapper on the straw, and then nudge it off one of the ends. It sits there compressed, until you begin dropping water on it, and then HUZZAH! A serpent grows!

This is from something called capillary action . When water hits the snake, it begins to spread throughout the paper due to water being attracted to oppositely charged molecules in the paper. As it spreads, due to adhesion, it takes other drops with it until the straw wrapper is wholly soaked. As the fibers absorb the water, the wrapper acts like a sponge, and grows as it twists and turns in front of you.

Step 7: Drops on Leaves

See how nature deals with the wet stuff! Many plant leaves are extremely hydrophobic , which means they repel water. This has to do with their structure, and namely something called the contact angle of the water drop and the leaf itself. Drop water on different parts of a plant, and you'll find different it acts in different ways. A common trait for broad leaves is that water drops form into beads.

We are still not fully sure as to why there is a prevalence of hydrophobic leaves in nature, but many believe that it is to help clean the leaves of dirt and would-be invading microbes. This also keeps them from getting damp, which would provide a host area for molds and other organisms as well. The plant most famous for its hydrophobia is the lotus plant, being the namesake of the lotus effect .

Wander around and test some leaves, and then you can see what they look like up close , and how humans have engineered materials and chemicals to have similar hydrophobic tendencies. This is also a place where you can see many examples of the water drop lens effect in nature.

Step 8: Water Drop Trampoline

With a little bit of laminar air flow, you can get water drops to hop around! Make a fistful of straws with skinny straws in the middle and wider straws on the outside, and put them in a mailing tube. Tape the tube to a blowdryer, and run it on cool. After stabilizing it and turning it on, you'll find that you can drop water and have them bounce up and down for a bit before falling off and being ripped apart.

The water drop trampoline relies a lot on pressure, the Bernoulli principle, laminar flow, and water's adhesion, which is quite amazing when you think about it. if you want a full Instructable on how to make this, check mine out here!

I'm excited to hear what other experiments and explorations you do with water drops! Share them in the comments below and I'll try to add some in as we go! Have fun and keep exploring.

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Penny Experiment with Water Drops

A penny experiment that demonstrates how water tension works and water can hold together in a dome shape – a super simple science experiment for kids!

Drop water on a penny and it just runs over the side, right?

Maybe not…

Maia was excited to show us a penny experiment she learned at school that demonstrated how water can hold together in a dome shape. This super simple science experiment requires only a penny, some water, and a dropper.

The Penny Experiment in Action

She showed us how we could carefully squeeze a drop of water at a time onto the top of the penny…

…and the droplets would combine to form a bubble of water.

Maia thought it looked a little like a snow globe (one of her favorite things).

We each tried the penny experiment to see how many drops of water it would take before it reached its limit. Because once it did, the water bubble burst and flowed over the edge of the penny.

Pretty cool, eh? We all had fun with this one. I think it’s definitely worth keeping it in mind for a rainy afternoon. Or just when you need a quick and easy activity for the kiddos.

By the way, if you want the technical explanation for why this works and what’s going on with the water, check out Steve Spangler Science .

3 More Favorite Simple Science Experiments for Kids

• The Rainbow Milk Science Experiment
• Make Painted Daisies
• Make a Baking Soda Volcano

P.S. Want even more science? Here’s my collection of The Best Kids Science Experiments to Try at Home .

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40 Simple Water Science Experiments for Kids

April 16, 2018 by Selena Robinson Leave a Comment

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Warmer weather means lots of water play and, for us, that means plenty of  simple water science experiments to try with the kids!

Since we’ve been homeschooling, I’ve learned that science doesn’t have to be a complicated subject to teach.

Many scientific concepts sound complicated (and really are amazingly intricate), but showing kids how they work doesn’t have to be complex.

Turns out that you can use a few household supplies and demonstrate how scientific principles work in a kid-friendly way!

And that’s why I’ve rounded up 40 easy water science experiments that would be great to share with kids – either indoors or outdoors!

Don’t miss our list of science experiments that you can do in just 15 minutes too!

1. Simple Light In Water Refraction Experiment – Look! We’re Learning!

2. Milk Jug Water Wheel Experiment – J Daniel 4’s Mom

3. Float Vs Sink Experiment – Teach Me Mommy

4. Leak-Proof Bag Science Experiment – Fun Learning for Kids

5. How to Make a Lava Lamp – Coffee Cups and Crayons

6. Measuring Water Beads – Blue Bear Wood

7. Water Balloon Parachute – Fantastic Fun and Learning

8. Food Coloring Fluid Mechanics Experiment – Mama Smiles

9. Measuring Buoyancy Experiment – KC Edventures

10. Color Mixing Experiment – Science Sparks

11. Tide Pool Science Experiment – Buggy and Buddy

12. Floating Peep Boats – Sixth Bloom

13. Traveling Water Experiment – The Wise Owl Factory

14. Simple Water Displacement Experiment – Life with Moore Babies

15. Ripple Water Experiment – J Daniel 4’s Mom

16. Why Does Water Rise STEM Experiment – STEAM Powered Family

17. Make a Rain Cloud In a Jar – Coffee Cups and Crayons

18. Water Xylophone Sound Experiment – Little Bins for Little Hands

19. Growing Mint in Water – Sloely

20. Sticky Ice Experiment – Capri Plus 3

See more of these awesome simple water science experiments on page 2!

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Water Experiments for Kids That Are a Big Hit in the Classroom

Written by Cassie (Teach Starter)

Are you teaching your students about water in your science classes? It’s time to pull out the water activities for kids that will wow them … while also helping your students learn about density, salinity, mass, and a whole lot more.

The teachers on the Teach Starter team have put together some water experiments for kids that can easily be done in a classroom with little prep — and without a ton of expensive items to buy. These water science activities are also easy for kids to recreate at home if they want to show off their newfound knowledge.

Water Experiments for Kids

Let me add, it’s always a great idea to try these experiments at home before you do them with your class for the first time. Just to make sure you know any little tweaks that are needed to illustrate the concepts you are exploring!

Understanding the Effects of Water Temperature

Use this water experiment for kids to explore the concept of temperature and its effect on the speed that molecules move. This science experiment for kids will quickly illustrate how molecules move faster in hot temperatures and slower in cold temperatures.

You will need:

• Room temperature water
• 3 stopwatches (or phones)

How to do this water science activity:

• Fill one glass with cold water, one with room temperature water, and one with hot water. (It is best to prepare the cold water and room temperature water earlier. Leave one glass in the refrigerator for at least an hour prior to the experiment. Leave another glass sitting out for at least an hour too, as if the water in your pipes is a bit cold this will reduce the efficacy of the experiment.)
• Place a stopwatch in front of each glass.
• Fill the dropper with food dye.
• Drop 2-3 drops of food dye in each of the glasses and observe how the food dye behaves in each different water temperature.
• Start the stopwatches when the food dye is dropped.
• Stop each watch as the food dye has mixed completely with the water.

Your students will be able to see how the food dye mixes quickly with the hot water because the molecules are moving quickly. It takes longer to mix in the room temperature water as the molecules move slower, and in the cold water, the food dye will take the longest to mix as the molecules move at the slowest speed of all three samples.

Eventually, the food dye will mix through the water in all three glasses. Students can predict how long each will take and then record the final times on each of the stopwatches.

Salt Water Density Experiments

Use this experiment to introduce the concepts of density, mass, salinity, and buoyancy.

In this experiment, you and your students will use one bowl of fresh water and one bowl of salt water to explore how salinity affects the buoyancy of different foods. For example, what happens when you put eggs in a bowl of fresh water and a bowl of salt water?

To get started, download and print the Salt Water Density Experiment resource , and prepare the materials described.

Challenge your students to guess whether they will have the same or different results if they try this same experiment using potatoes in place of the eggs.

This experiment also uses food dye to explore how liquid molecules behave differently in fresh water and saltwater.

When your students understand how water behaves differently depending on its density, they can begin to understand more about topics such as:

• the effects of freshwater runoff from melted sea ice in the Antarctic
• how different parts of the ocean have different levels of salinity
• why objects that would normally sink (like people) can float in bodies of water with high salinity like the Dead Sea in the Middle East and the Great Salt Lake in the United States
• how salinity affects the different layers of the ocean and the types of marine life that can live in each layer.

Refraction of Light Science Activity

This water experiment for kids is incredibly simple to set up, and it will help your students better understand refraction, the change of direction of light waves, when they hit water.

All you need is:

• A Glass of water

Draw something on a piece of paper. An arrow is a great visual to start this science activity as it is obvious what happens when you put the glass of water in front of the drawn arrow. But you don’t have to limit it to arrows. Get creative and draw anything you would like to see through the glass.

When the light is passing through the glass of water, it refracts or bends. The glass of water acts as a cylindrical convex lens and produces an inverted image.

Create a fair test by changing one variable. What happens if you change the size of the glass? Or what if you change the liquid variable? Does it change the result?

Teach your students more about reflection and refraction with these resources:

[resource:4701421][resource:2674282]

Create a Lava Lamp Science Activity

No need to head out to buy a lava lamp. You can make your own “lamp” with this fun water activity for kids that teaches about the changes of density as gas is added to or taken away from the water.

• Two glasses
• Vegetable oil
• Food coloring
• Alka-Seltzer tablets

Firstly, mix half a cup of water with some drops of food coloring. You can make two different batches with different colors if you wish to make more than one lava lamp.

Then, fill a glass with vegetable oil (3/4 full). Pour some of the colored mixture into the oil, being careful not to fill the glass too much.

Add one Alka-Seltzer tablet, and watch the chemical reaction…

The Alka-seltzer tablets react with the water to produce carbon dioxide gas bubbles in this fun water activity! These stick to the water droplets. The water/gas combo is less dense than the oil, so they rise to the top of the glass!

Make this a fair test by changing the amount of Alka-seltzer added. In one glass you can add one tablet, another can have two tablets, and another can have three. What happens when you change up the water experiment?

For more water density fun, try these resources:

[resource:1872818][resource:640196][resource:4680428]

Moving Water Experiment

This water activity for kids explores water movement and helps kids understand capillary action. It does take a couple of hours for the results to finalize, so it’s best an experiment that you set and forget, checking back in throughout the day with your class. Perhaps take a picture every half hour to monitor your progress!

Aim: To investigate the movement of water when it has paper towel placed in it.

• A measuring cup
• 4 pieces of paper towel
• Red, blue and yellow food dye
• 5  clear drinking cups/glasses (jars work well too!)
• water – enough to pour equal amounts into 3 of the cups
• 3  mixing spoons
• Line up 5 cups. Fill cups number 1, 3, and 5 with equal amounts of water.
• Place equal drops of food dye into each cup of water – place blue into one cup, red into another, and yellow into the final cup. Mix each cup thoroughly with a new spoon to prevent cross-contamination.
• Place a scrunched piece of paper towel so that it creates a bridge between each cup in the line. The paper towel must be quite deep in the water in each cup.
• Watch what happens over the next few hours and record your results!

This is similar to the way that the roots of a tree pull water up and out of the ground. You can observe the movement and direction of the water by watching the water move up the paper towel, and observing the empty cups filling with a ‘new’ colored water as the two primary colors on either side mix together.

Possible questions to ask:

• What will the food dye from one cup do when it mixes with the dye from another cup?
• Why do you think the water didn’t move backward once the empty cups started to fill up?
• Why do you think the water stopped moving once the cups leveled out?

Check out this fun capillary action water activity for kids using flowers or this one using paper towels and capillary action to make roses that the kids can bring home to gift to someone they love.

For more science experiments for kids and more ways to teach science to elementary schoolers, check out our full array of science teaching resources !

30 Buzzing Facts About Bees to Excite Kids About Nature

Everyone benefits from the busyness of bees which is why these bee facts will help inspire your students to appreciate and protect them!

21 Epic Last Day of School Activities to Kick Off Summer Break

Looking for easy last day of school ideas for elementary or middle school? These quick and fun end of year classroom activities will help you finish off your year just right!

70 1st Grade Books to Add to Your Classroom Reading Corner This Year

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22 Fun Groundhog Facts to Share With Your Class on Groundhog Day

Need fun groundhog facts to share with your students this Groundhog Day? Find out what groundhogs eat, where they live and why we let them predict the weather!

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Surface Tension of Water Demonstration

April 17, 2019 By Emma Vanstone 3 Comments

These super simple investigations are great for demonstrating the surface tension of water .

What is surface tension?

Surface tension  is a force which causes a layer of liquid to behave like an elastic sheet or skin.

Molecules of water are more attracted to each other than other molecules, as water is a polar molecule. The positive hydrogen end of one molecule is attracted to the negative oxygen end of another water molecule. The surface water molecules only have air above them, so they are pulled down, creating surface tension.

The high surface tension of water allows insects to walk over it. Pond skaters have long, hairy legs, allowing them to spread their weight over a wide area. They press very gently on the water’s surface so as not to break through it.

In a container of water, molecules below the surface are pulled together ( or attracted to each other ) equally in all directions, but those on top are pulled together more tightly, as they don’t have water molecules above them; this draws them together to form a ‘skin’. It is this skin ( surface tension ) that stops items on the surface from sinking.

Surface Tension Holes Experiment

You’ll need.

A big bowl of water

Some ground pepper (black so you can see it) or any other ground product with colour

Washing up liquid ( dish soap )

Once the water settles, sprinkle the ground pepper over the top.

Drip some washing-up liqu id in the middle of the bowl and watch what happens.

A hole appears in the centre as the pepper moves outwards. This is your surface tension hole !

If you want to repeat the demonstration, you’ll need to wash out the bowl thoroughly to remove any traces of the dish soap ( washing up liquid ), or the effect won’t be as dramatic.

Why does this happen?

The surface tension hole is caused by the washing up liquid reducing the surface tension of the water. This allows the particles of water at the surface to spread out, starting from where the washing-up liquid was added.

More Surface Tension Experiments for Kids

Frugal Fun for Boys has an excellent surface tension investigation using a coin and different liquids !

You can use washing-up liquid to disrupt the surface tension of water to race lolly sticks .

In a magic milk experiment , the washing up liquid disrupts the surface tension of the milk, which makes food colouring spread out just like the pepper and water.

Another surface tension experiment is where you make a shape on the surface of the water with cocktail sticks and drop some washing-up liquid in the centre to force the sticks apart.

Watch how water behaves on the space station with this NASA video.

Try filling a bowl half full with water and carefully placing a paperclip on the top, so it floats. Mix a little washing-up liquid in a cup with water and gently pour it into the bowl; the paper clip will sink as the water can no longer support the weight of the paper clip after the washing-up liquid disrupts the surface tension of the water.

Science concepts

Surface tension

Last Updated on July 8, 2023 by Emma Vanstone

Safety Notice

Science Sparks ( Wild Sparks Enterprises Ltd ) are not liable for the actions of activity of any person who uses the information in this resource or in any of the suggested further resources. Science Sparks assume no liability with regard to injuries or damage to property that may occur as a result of using the information and carrying out the practical activities contained in this resource or in any of the suggested further resources.

These activities are designed to be carried out by children working with a parent, guardian or other appropriate adult. The adult involved is fully responsible for ensuring that the activities are carried out safely.

Reader Interactions

October 16, 2011 at 3:00 pm

Great activity, I am going to try it with my daughter! I love how you call it “washing up liquid” – I call it that too. 🙂

October 16, 2011 at 9:26 pm

Thanks, glad you like it!

October 21, 2011 at 6:01 pm

So many great ideas come form this blog! Thank you for linking up to the The Sunday Showcase

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Science Experiments

Upside Down Glass of Water Science Experiment

Have you ever tried turning a glass of water upside down without spilling it? It seems impossible! Both kids and adults will be amazed by this experiment that appears to defy gravity.

With just a few simple household items, you can try this simple and fun science experiment where kids can get see the effects of air pressure in action. Printable instructions, a demonstration video, and an easy to understand explanation of how it works are included below.

Helpful Tip: Be sure to try this experiment over a sink or large container lest you accidentally make a BIG wet mess!

JUMP TO SECTION:   Instructions  |  Video Tutorial  |  How it Works

Supplies Needed

• Drinking Glass
• Thick Sheet of Paper that is long and wide enough to cover the entire mouth of the glass. (We used a piece of poster board)
• Large Container or Sink

Upside Down Glass of Water Science Lab Kit – Only $5

Use our easy Upside Down Glass of Water Science Lab Kit to grab your students’ attention without the stress of planning!

It’s everything you need to  make science easy for teachers and fun for students  — using inexpensive materials you probably already have in your storage closet!

Upsidedown Glass of Water Science Experiment Instructions

Step 1 – Begin by filling the empty glass with water. Ensure that the water is completely to the top of the glass. If there is any space between the water and the paper, the experiment won’t work.

Step 2 – Gently place the paper on the top of the glass.

Step 3 – Move the glass over the container or sink. 

Step 4 – Gently place your hand on the paper, then flip the glass over. What do you think will happen if you remove your hand? Write down your hypothesis (prediction) and then follow the steps below.

Step 5 – Remove your hand from the bottom and watch in amazement as the paper stays covering the glass and the water doesn’t spill out. Do you know why this happens? Find out the answer in the how does this experiment work section below.

Upside Down Water Glass Video

How Does the Experiment Work?

The reason this experiment works is because of air pressure! Air pressure is the weight of a column of air pushing down on an area. While we cannot feel it, the air is heavy! The weight of the air pushing down on all objects on Earth is the same as the combined weight of three cars! The reason we don’t feel this extreme weight is that the molecules in air push evenly in all directions – up, down, sideways, diagonally. In this experiment, the air pushing up from underneath the paper is strong enough to overcome the weight of the water pushing down on the paper. Because of the air pressure pushing up on the card, the card will stay on the glass and the water will not spill out.

Do note that while the paper will stay for a while, the paper will become saturated and it will fall eventually.

More Science Fun

If you enjoyed this experiment, then you’ll definitely enough these other cool science experiments that also highlight the power of air.

• Balloon Rocket – Make a balloon that flies across the room like a rocket
• Keep Towel Dry Under Water – Use simple science to keep the paper towel dry after submerging it in water
• Put a Straw through a Raw Potato – Yes, you can easily stick a drinking straw through a hard raw potato

I hope you enjoyed the experiment. Here are some printable instructions:

Upside down Glass of Water Experiment

Instructions.

• Begin by filling the empty glass with water. Helpful Tip: Ensure that the water is completely to the top of the glass. If there is any space between the water and the paper, the experiment won’t work.
• Gently place the paper on the top of the glass.
• Move the glass over the container or sink.
• Gently place your hand on the paper, then flip the glass over.
• Remove your hand from the bottom and watch in amazement as the paper stays covering the glass and the water doesn’t spill out.

Reader Interactions

February 18, 2023 at 4:11 pm

Air Pressure.

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Copyright © 2024 · Cool Science Experiments HQ

Life from a drop of rain: New research suggests rainwater helped form the first protocell walls

August 21, 2024

By Paul Dailing

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One of the major unanswered questions about the origin of life is how droplets of RNA floating around the primordial soup turned into the membrane-protected packets of life we call cells.

A new paper by engineers from the University of Chicago’s Pritzker School of Molecular Engineering (UChicago PME) , the University of Houston’s Chemical Engineering Department , and biologists from the UChicago Chemistry Department, have proposed a solution.

In the paper, published today in Science Advances , UChicago PME postdoctoral researcher Aman Agrawal and his co-authors – including UChicago PME Dean Emeritus Matthew Tirrell and Nobel Prize-winning biologist Jack Szostak – show how rainwater could have helped create a meshy wall around protocells 3.8 billion years ago, a critical step in the transition from tiny beads of RNA to every bacterium, plant, animal, and human that ever lived.

“This is a distinctive and novel observation,” Tirrell said.

The research looks at “coacervate droplets” – naturally occurring compartments of complex molecules like proteins, lipids, and RNA. The droplets, which behave like drops of cooking oil in water, have long been eyed as a candidate for the first protocells. But there was a problem. It wasn’t that these droplets couldn’t exchange molecules between each other, a key step in evolution, the problem was that they did it too well, and too fast.

Any droplet containing a new, potentially useful pre-life mutation of RNA would exchange this RNA with the other RNA droplets within minutes, meaning they would quickly all be the same. There would be no differentiation and no competition – meaning no evolution.

And that means no life.

“If molecules continually exchange between droplets or between cells, then all the cells after a short while will look alike, and there will be no evolution because you are ending up with identical clones,” Agrawal said.

Engineering a solution

Life is by nature interdisciplinary, so Szostak, the director of UChicago’s Chicago Center for the Origins of Life , said it was natural to collaborate with both UChicago PME , UChicago’s interdisciplinary school of molecular engineering, and the chemical engineering department at the University of Houston.

“Engineers have been studying the physical chemistry of these types of complexes – and polymer chemistry more generally – for a long time. It makes sense that there's expertise in the engineering school,” Szostak said. “When we're looking at something like the origin of life, it's so complicated and there are so many parts that we need people to get involved who have any kind of relevant experience.”

In the early 2000s , Szostak started looking at RNA as the first biological material to develop. It solved a problem that had long stymied researchers looking at DNA or proteins as the earliest molecules of life.

“It's like a chicken-egg problem. What came first?” Agrawal said. “DNA is the molecule which encodes information, but it cannot do any function. Proteins are the molecules which perform functions, but they don't encode any heritable information.”

Researchers like Szostak theorized that RNA came first, “taking care of everything” in Agrawal’s words, with proteins and DNA slowly evolving from it.

“RNA is a molecule which, like DNA, can encode information, but it also folds like proteins so that it can perform functions such as catalysis as well,” Agrawal said.

RNA was a likely candidate for the first biological material. Coacervate droplets were likely candidates for the first protocells. Coacervate droplets containing early forms of RNA seemed a natural next step.

That is until Szostak poured cold water on this theory, publishing a paper in 2014 showing that RNA in coacervate droplets exchanged too rapidly.

“You can make all kinds of droplets of different types of coacervates, but they don't maintain their separate identity. They tend to exchange their RNA content too rapidly. That’s been a long-standing problem,” Szostak said. “What we showed in this new paper is that you can overcome at least part of that problem by transferring these coacervate droplets into distilled water – for example, rainwater or freshwater of any type – and they get a sort of tough skin around the droplets that restricts them from exchanging RNA content.”

‘A spontaneous combustion of ideas’

Agrawal started transferring coacervate droplets into distilled water during his PhD research at the University of Houston, studying their behavior under an electric field. At this point, the research had nothing to do with the origin of life, just studying the fascinating material from an engineering perspective.

“Engineers, particularly Chemical and Materials, have good knowledge of how to manipulate material properties such as interfacial tension, role of charged polymers, salt, pH control, etc.,” said University of Houston Prof. Alamgir Karim , Agrawal’s former thesis advisor and a senior co-author of the new paper. “These are all key aspects of the world popularly known as ‘complex fluids’ - think shampoo and liquid soap.”

Agrawal wanted to study other fundamental properties of coacervates during his PhD. It wasn’t Karim’s area of study, but Karim had worked decades earlier at the University of Minnesota under one of the world’s top experts – Tirrell, who later became founding dean of the UChicago Pritzker School of Molecular Engineering.

During a lunch with Agrawal and Karim, Tirrell brought up how the research into the effects of distilled water on coacervate droplets might relate to the origin of life on Earth. Tirrell asked where distilled water would have existed 3.8 billion years ago.

“I spontaneously said ‘rainwater!’ His eyes lit up and he was very excited at the suggestion,” Karim said. “So, you can say it was a spontaneous combustion of ideas or ideation!”

Tirrell brought Agrawal’s distilled water research to Szostak, who had recently joined the University of Chicago to lead what was then called the Origins of Life Initiative. He posed the same question he had asked Karim.

“I said to him, ‘Where do you think distilled water could come from in a prebiotic world?’” Tirrell recalled. “And Jack said exactly what I hoped he would say, which was rain.”

Working with RNA samples from Szostak, Agrawal found that transferring coacervate droplets into distilled water increased the time scale of RNA exchange – from mere minutes to several days. This was long enough for mutation, competition, and evolution.

“If you have protocell populations that are unstable, they will exchange their genetic material with each other and become clones. There is no possibility of Darwinian evolution,” Agrawal said. “But if they stabilize against exchange so that they store their genetic information well enough, at least for several days so that the mutations can happen in their genetic sequences, then a population can evolve.”

Rain, checked

Initially, Agrawal experimented with deionized water, which is purified under lab conditions. “This prompted the reviewers of the journal who then asked what would happen if the prebiotic rainwater was very acidic,” he said.

Commercial lab water is free from all contaminants, has no salt, and lives with a neutral pH perfectly balanced between base and acid. In short, it’s about as far from real-world conditions as a material can get. They needed to work with a material more like actual rain.

What’s more like rain than rain?

“We simply collected water from rain in Houston and tested the stability of our droplets in it, just to make sure what we are reporting is accurate,” Agrawal said.

In tests with the actual rainwater and with lab water modified to mimic the acidity of rainwater, they found the same results. The meshy walls formed, creating the conditions that could have led to life.

The chemical composition of the rain falling over Houston in the 2020s is not the rain that would have fallen 750 million years after the Earth formed, and the same can be said for the model protocell system Agrawal tested. The new paper proves that this approach of building a meshy wall around protocells is possible and can work together to compartmentalize the molecules of life, putting researchers closer than ever to finding the right set of chemical and environmental conditions that allow protocells to evolve.

“The molecules we used to build these protocells are just models until more suitable molecules can be found as substitutes,” Agrawal said. “While the chemistry would be a little bit different, the physics will remain the same.”

Citation: “Did the exposure of coacervate droplets to rain make them the first stable protocells?” Agrawal et al, Science Advances , August 21, 2024. DOI: 10.1126/sciadv.adn9657

A Nobel-winning Biologist, Two Engineering Schools, and a Vial of Houston Rainwater Cast New Light on the Origin of Life on Earth

One of the major unanswered questions about the origin of life is how droplets of RNA floating around the primordial soup turned into the membrane-protected packets of life we call cells. 

A new paper by engineers from the University of Houston’s William A. Brookshire Department of Chemical Engineering (UH ChBE) and the University of Chicago’s Pritzker School of Molecular Engineering (UChicago PME) , and biologists from the UChicago Chemistry Department have proposed a solution. 

In the paper published today in Science Advances , UH ChBE’s former graduate student Aman Agrawal (now a postdoctoral researcher at UChicago PME) and his co-authors – including UH ChBE’s Alamgir Karim , UChicago PME Dean Emeritus Matthew Tirrell and Nobel Prize-winning biologist Jack Szostak – show how rainwater could have helped create a meshy wall around protocells 3.8 billion years ago, a critical step in the transition from tiny beads of RNA to every bacterium, plant, animal, and human that ever lived. 

“While it is impossible to know the exact conditions on early Earth, our experiments show that this pathway for stabilizing protocells might have been a critical step in enabling evolution in these protocells,” said Karim. Karim is UH Dow Chair and Welch Foundation Professor of chemical and biomolecular engineering, and director of both the International Polymer & Soft Matter Center and the Materials Engineering Program at UH.  

“This is a game-changing discovery in the context of pre-biotic life,” Karim said.

The research looks at “coacervate droplets” – naturally occurring compartments of complex molecules like proteins, lipids, and RNA. The droplets, which behave like drops of cooking oil in water, have long been eyed as a candidate for the first protocells. But there was a problem. It wasn’t that these droplets couldn’t exchange molecules between each other, a key step in evolution, the problem was that they did it too well, and too fast. 

Any droplet containing a new, potentially useful pre-life mutation of RNA would exchange this RNA with the other RNA droplets within minutes, meaning they would quickly all be the same. There would be no differentiation and no competition – meaning no evolution. 

And that means no life. 

“If molecules continually exchange between droplets or between cells, then all the cells after a short while will look alike, and there will be no evolution because you are ending up with identical clones,” Agrawal said. 

Engineering a solution

Life is by nature interdisciplinary, so Szostak, the director of UChicago’s Chicago Center for the Origins of Life , said it was natural to collaborate with both UChicago PME , UChicago’s interdisciplinary school of molecular engineering, and the chemical engineering department at the University of Houston.  

“Engineers have been studying the physical chemistry of these types of complexes – and polymer chemistry more generally – for a long time. It makes sense that there's expertise in the engineering school,” Szostak said. “When we're looking at something like the origin of life, it's so complicated and there are so many parts that we need people to get involved who have any kind of relevant experience.” 

In the early 2000s , Szostak started looking at RNA as the first biological material to develop. It solved a problem that had long stymied researchers looking at DNA or proteins as the earliest molecules of life. 

“It's like a chicken-egg problem. What came first?” Agrawal said. “DNA is the molecule which encodes information, but it cannot do any function. Proteins are the molecules which perform functions, but they don't encode any heritable information.” 

Researchers like Szostak theorized that RNA came first, “taking care of everything” in Agrawal’s words, with proteins and DNA slowly evolving from it. 

“RNA is a molecule which, like DNA, can encode information, but it also folds like proteins so that it can perform functions such as catalysis as well,” Agrawal said.  

RNA was a likely candidate for the first biological material. Coacervate droplets were likely candidates for the first protocells. Coacervate droplets containing early forms of RNA seemed a natural next step.  

That is until Szostak poured cold water on this theory, publishing a paper in 2014 showing that RNA in coacervate droplets exchanged too rapidly.  

“You can make all kinds of droplets of different types of coacervates, but they don't maintain their separate identity. They tend to exchange their RNA content too rapidly. That’s been a long-standing problem,” Szostak said. “What we showed in this new paper is that you can overcome at least part of that problem by transferring these coacervate droplets into distilled water – for example, rainwater or freshwater of any type – and they get a sort of tough skin around the droplets that restricts them from exchanging RNA content.” 

‘A spontaneous combustion of ideas’

Agrawal started transferring coacervate droplets into distilled water during his PhD research at the University of Houston, studying their behavior under an electric field. At this point, the research had nothing to do with the origin of life, just studying the fascinating material from an engineering perspective.

“Engineers, particularly Chemical and Materials, have good knowledge of how to manipulate material properties such as interfacial tension, role of charged polymers, salt, pH control, etc.,” said University of Houston Prof. Alamgir Karim , Agrawal’s former thesis advisor and a senior co-author of the new paper. “These are all key aspects of the world popularly known as ‘complex fluids’ - think shampoo and liquid soap.” 

Agrawal wanted to study other fundamental properties of coacervates during his PhD. It wasn’t Karim’s area of study, but Karim had worked decades earlier at the University of Minnesota under one of the world’s top experts – Tirrell, who later became founding dean of the UChicago Pritzker School of Molecular Engineering.  

During a lunch with Agrawal and Karim, Tirrell brought up how the research into the effects of distilled water on coacervate droplets might relate to the origin of life on Earth. Tirrell asked where distilled water would have existed 3.8 billion years ago.

“I spontaneously said ‘rainwater!’ His eyes lit up and he was very excited at the suggestion,” Karim said. “So, you can say it was a spontaneous combustion of ideas or ideation!”

Tirrell brought Agrawal’s distilled water research to Szostak, who had recently joined the University of Chicago to lead what was then called the Origins of Life Initiative. He posed the same question he had asked Karim. 

“I said to him, ‘Where do you think distilled water could come from in a prebiotic world?’” Tirrell recalled. “And Jack said exactly what I hoped he would say, which was rain.” 

Working with RNA samples from Szostak, Agrawal found that transferring coacervate droplets into distilled water increased the time scale of RNA exchange – from mere minutes to several days. This was long enough for mutation, competition, and evolution. 

“If you have protocell populations that are unstable, they will exchange their genetic material with each other and become clones. There is no possibility of Darwinian evolution,” Agrawal said. “But if they stabilize against exchange so that they store their genetic information well enough, at least for several days so that the mutations can happen in their genetic sequences, then a population can evolve.” 

Rain, checked

Initially, Agrawal experimented with deionized water, which is purified under lab conditions. “This prompted the reviewers of the journal who then asked what would happen if the prebiotic rainwater was very acidic,” he said.  

Commercial lab water is free from all contaminants, has no salt, and lives with a neutral pH perfectly balanced between base and acid. In short, it’s about as far from real-world conditions as a material can get. They needed to work with a material more like actual rain.  

What’s more like rain than rain? 

“We simply collected water from rain in Houston and tested the stability of our droplets in it, just to make sure what we are reporting is accurate,” Agrawal said. Agrawal and  fellow UH graduate student Anusha Vonteddu grabbed a couple of beakers from Karim’s lab to collect some rainwater just outside the Agrawal Engineering Research Building during a downpour. 

“Agrawal and Vonteddu, with their rain samples in beakers, set out to prove our major hypothesis that rainwater could have stabilized the protocells on early Earth,” said Karim. 

In tests with the actual rainwater and with lab water modified to mimic the acidity of rainwater, they found the same results. The meshy walls formed, creating the conditions that could have led to life.  “This is a game-changing discovery in the context of pre-biotic life,” Karim said. 

The chemical composition of the rain falling over Houston in the 2020s is not the rain that would have fallen 750 million years after the Earth formed, and the same can be said for the model protocell system Agrawal tested. The new paper proves that this approach of building a meshy wall around protocells is possible and can work together to compartmentalize the molecules of life, putting researchers closer than ever to finding the right set of chemical and environmental conditions that allow protocells to evolve. 

“The molecules we used to build these protocells are just models until more suitable molecules can be found as substitutes,” Agrawal said. “While the chemistry would be a little bit different, the physics will remain the same.” 

Written at University of Chicago’s Pritzker School of Molecular Engineering and edited by the University of Houston with permission.

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US government report says fluoride at twice the recommended limit is linked to lower IQ in kids

FILE - Water flows from a water fountain in Concord, N.H., on Friday, Jan. 7, 2011. (AP Photo/Jim Cole, File)

FILE - A child rinses a toothbrush in San Francisco on June 18, 2019. (Gabrielle Lurie/San Francisco Chronicle via AP, File)

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NEW YORK (AP) — A U.S. government report expected to stir debate concluded that fluoride in drinking water at twice the recommended limit is linked with lower IQ in children.

The report, based on an analysis of previously published research, marks the first time a federal agency has determined — “with moderate confidence” — that there is a link between higher levels of fluoride exposure and lower IQ in kids. While the report was not designed to evaluate the health effects of fluoride in drinking water alone, it is a striking acknowledgment of a potential neurological risk from high levels of fluoride.

Fluoride strengthens teeth and reduces cavities by replacing minerals lost during normal wear and tear , according to the U.S. Centers for Disease Control and Prevention. The addition of low levels of fluoride to drinking water has long been considered one of the greatest public health achievements of the last century.

“I think this (report) is crucial in our understanding” of this risk, said Ashley Malin, a University of Florida researcher who has studied the effect of higher fluoride levels in pregnant women on their children. She called it the most rigorously conducted report of its kind.

The long-awaited report released Wednesday comes from the National Toxicology Program, part of the Department of Health and Human Services. It summarizes a review of studies, conducted in Canada, China, India, Iran, Pakistan, and Mexico, that concludes that drinking water containing more than 1.5 milligrams of fluoride per liter is consistently associated with lower IQs in kids.

The report did not try to quantify exactly how many IQ points might be lost at different levels of fluoride exposure. But some of the studies reviewed in the report suggested IQ was 2 to 5 points lower in children who’d had higher exposures.

Since 2015, federal health officials have recommended a fluoridation level of 0.7 milligrams per liter of water, and for five decades before the recommended upper range was 1.2. The World Health Organization has set a safe limit for fluoride in drinking water of 1.5.

The report said that about 0.6% of the U.S. population — about 1.9 million people — are on water systems with naturally occurring fluoride levels of 1.5 milligrams or higher.

“The findings from this report raise the questions about how these people can be protected and what makes the most sense,” Malin said.

The 324-page report did not reach a conclusion about the risks of lower levels of fluoride, saying more study is needed. It also did not answer what high levels of fluoride might do to adults.

The American Dental Association, which champions water fluoridation, had been critical of earlier versions of the new analysis and Malin’s research. Asked for comment, a spokeswoman late Wednesday afternoon emailed that the organization’s experts were still reviewing the report.

Fluoride is a mineral that exists naturally in water and soil. About 80 years ago, scientists discovered that people whose water supplies naturally had more fluoride also had fewer cavities, triggering a push to get more Americans to use fluoride for better dental health.

In 1945, Grand Rapids, Michigan became the first U.S. city to start adding fluoride to tap water. In 1950, federal officials endorsed water fluoridation to prevent tooth decay, and continued to promote it even after fluoride toothpaste brands hit the market several years later. Though fluoride can come from a number of sources, drinking water is the main source for Americans, researchers say.

Officials lowered their recommendation for drinking water fluoride levels in 2015 to address a tooth condition called fluorosis, that can cause splotches on teeth and was becoming more common in U.S. kids.

Separately, the Environmental Protection Agency has maintained a longstanding requirement that water systems cannot have more than 4 milligrams of fluoride per liter. That standard is designed to prevent skeletal fluorosis, a potentially crippling disorder which causes weaker bones, stiffness and pain.

But more and more studies have increasingly pointed to a different problem, suggesting a link between higher levels of fluoride and brain development. Researchers wondered about the impact on developing fetuses and very young children who might ingest water with baby formula. Studies in animals showed fluoride could impact neurochemistry cell function in brain regions responsible for learning, memory, executive function and behavior.

In 2006, the National Research Council, a private nonprofit organization in Washington, D.C., said limited evidence from China pointed to neurological effects in people exposed to high levels of fluoride. It called for more research into the effect of fluoride on intelligence.

After more research continued to raise questions, the National Toxicology Program in 2016 started working on a review of the available studies that could provide guidance on whether new fluoride-limiting measures were needed.

There were earlier drafts but the final document has repeatedly been held up. At one point, a committee of experts said available research did not support an earlier draft’s conclusions.

“Since fluoride is such an important topic to the public and to public health officials, it was imperative that we made every effort to get the science right,” said Rick Woychik, director of the National Toxicology Program, in a statement.

Malin said it makes sense for pregnant women to lower their fluoride intake, not only from water but also from certain types of tea. It might also make sense to have policy discussions about whether to require fluoride-content on beverage labels, she said.

The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute’s Science and Educational Media Group. The AP is solely responsible for all content.

Yeti just dropped a new limited-edition pink color to its collection of coolers, tumblers, mugs, more

• Published: Aug. 27, 2024, 9:05 p.m.

Yeti just launched the new limited-edition Sandstone Pink Collection that's inspired by the Valley of Fire. Yeti

• Dawn Magyar | NJ Advance Media for NJ.com

If Yeti’s pink color drops have been some of your favorites, you’re in for a treat with the new Sandstone Pink Collection.

The new Sandstone Pink is a limited-edition seasonal color that’s popping up in Yeti’s Rambler tumblers , Rambler mugs , Tundra coolers , Hopper soft coolers , and more gear.

This new pink hue drop adds to Yeti’s recent pink color drops, including Tropical Pink , Wildflower Fuchsia , and Power Pink . The Sandstone Pink Collection ranges in price from $9-$350 and is now available directly from Yeti for purchase.

Inspired by the red sandstone formations in the Mohave Desert that are nestled in Nevada’s Valley of Fire State Park, the new Sandstone Pink Collection builds upon the brilliant pink hues of the area. These sandstone-colored wonders are over 2,000 years old, featuring bold rocks and petroglyph carvings that spread across 40,000 acres of the park.

While the new Sandstone Pink Collection is currently available online from Yeti, we don’t expect the most popular drinkware and gear to stick around for long. So, if you have a must-have in this limited-edition pink shade, grab it while you can.

Yeti also includes free shipping on qualified online orders of $40 and up. It also offers free 30-day returns.

Everything in the YETI Sandstone Pink Collection

Here’s a look at some of the best coolers, tumblers, and more you can grab from Yeti’s new Sandstone Pink Collection.

• Rambler 35 oz Straw Mug for $42
• Rambler 20 oz Tumbler for $35
• Rambler 18 oz Water Bottle for $30
• Rambler 10 oz Stackable Mug for $25
• Roadie 24 Hard Cooler for $250
• Tundra 45 Hard Cooler for $300
• Hopper Flip 12 Soft Cooler for $250
• Hopper M20 Backpack Soft Cooler for $325
• Rambler 20 oz Cocktail Shaker for $60
• Rambler 12 oz Colster Can Cooler for $25
• Rambler 64 oz Water Bottle for $65
• Camino 20 Carryall Tote Bag for $130

Shop for more Yeti gear in the new Sandstone Pink Collection here.

The Biggest Tumbler & Water Bottle Releases From Stanley, Owala and More in 2024

• Amazon has Stanley’s leakproof IceFlow water bottles on sale for up to 25% off with free delivery
• Owala’s new Disney Pocahontas water bottle drop is going to blow you away — here’s where to snag it
• Simple Modern just dropped a ‘spooktacular’ new Halloween tumbler collection
• Stanley just dropped a big surprise Quencher color that’s inspired by a fan-favorite tumbler shade
• Owala dropped the Great American Road Trip water bottle collection, and you can still grab it now

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Lake Erie Water levels to drop in the fall. How do they compare to historic levels?

The Lake Erie water levels will begin to drop as temperatures begin to fall in the coming months, the U.S. Army Corps of Engineers projects.

In July, the water levels reached a high of 573.03 feet and a low of 572.80 feet. The July levels are above the long-term average level of 572.01 feet.

These levels were well below the record levels recorded in 2019 when Lake Erie reached 574.21 feet, but above the lowest-ever recorded level in 1934 at 569 feet.

The water levels for August are still above the long-term average of 571.82 feet.

The water levels are showing no signs of significant change, but the U.S. Army Corps of Engineers projects the levels will start to drop in the upcoming months.

More: Lake Erie was at record levels in 2019. Where things stand, and a forecast, 5 years later.

Lake Erie water levels for August

The lake water levels recorded between Aug. 1-25 have ranged between a maximum level of 572.97 feet and a low of 572.51 feet.

The levels are similar to the July levels but are showing signs of dropping.

More: Lake Erie alligator search ongoing. What we know

What will the Lake Erie water levels be in the upcoming months?

Here are the water level forecasts for Lake Erie from the U.S. Army Corps for the next five months:

• September: upper levels 572.64 feet, lower levels 571.59 feet.
• October: upper levels 572.37 feet, lower levels 571.13 feet.
• November: upper levels 572.24 feet, lower levels 570.8 feet.
• December: upper levels 572.37 feet, lower levels 570.8 feet.

Contact Nicholas Sorensen at [email protected] .