science experiments with paper cups

50 best science project ideas using paper cups

In this post you will find about 50 science projects that you can do using paper cups

Paper Cup Telephone : Explore sound transmission by creating a simple telephone using two paper cups and string.

Paper Cup Wind Turbine : Build a mini wind turbine using a paper cup and investigate its energy generation capabilities.

Paper Cup Hot Air Balloon : Construct a small hot air balloon from a paper cup and tissue paper to study buoyancy and air pressure.

Paper Cup Spectroscope : Create a spectroscope using a paper cup and a diffraction grating to analyze light sources.

Paper Cup Lungs Model : Build a model of human lungs using paper cups and straws to demonstrate respiratory function.

Paper Cup Anemometer : Design an anemometer to measure wind speed using rotating paper cups.

Paper Cup Pulley System : Build a pulley system using paper cups and string to demonstrate principles of mechanical advantage.

Paper Cup Electromagnet : Create an electromagnet using a paper cup, wire, and battery to study magnetism.

Paper Cup Cartesian Diver : Make a Cartesian diver using a paper cup and a dropper to explore buoyancy and pressure.

Paper Cup Seed Starter : Use paper cups as biodegradable seed starters and monitor plant growth.

Paper Cup Geodesic Dome : Construct a geodesic dome using interconnected paper cups to understand geometry and stability.

Paper Cup Candle Heater : Design a heater using tea light candles and paper cups to study heat transfer.

Paper Cup Marble Run : Build a marble run using paper cups and cardboard to explore kinetic energy and motion.

Paper Cup Solar Still : Create a solar still using a paper cup and plastic wrap to purify water through evaporation and condensation.

Paper Cup Balance Scale : Build a balance scale using paper cups and a ruler to explore concepts of weight and balance.

Paper Cup Air pollution model : Create air pollution model using paper cups.

Paper Cup Pinhole Camera : Convert a paper cup into a pinhole camera to capture images using the principles of light and optics.

Paper Cup Wind Vane : Design a wind vane using a paper cup and a pencil to indicate wind direction.

Paper Cup Ecosystem : Create a closed ecosystem using paper cups, soil, plants, and insects to study ecological interactions.

Paper Cup Pneumatic System : Build a pneumatic system using paper cups and syringes to explore air pressure.

Paper Cup Straw Flute : Make a musical instrument by attaching straws to paper cups and explore sound waves.

Paper Cup Solar Cooker : Construct a solar cooker using a paper cup and aluminum foil to harness solar energy for cooking.

Paper Cup Density Tower : Layer liquids of different densities in a paper cup to create a colorful density tower.

Paper Cup Rainbow Spinner : Create a rainbow spinner using a paper cup and a CD to study color perception.

Paper Cup Seed Dispenser : Design a seed dispenser using a paper cup and a valve mechanism for controlled seed distribution.

Paper Cup Cartesian Roller Coaster : Build a roller coaster track using paper cups and cardboard to demonstrate potential and kinetic energy.

Paper Cup Mini eco friendly house : Make a mini ecofriendly using a paper cup

Paper Cup Solar Water Heater : Design a solar water heater using a paper cup, black paper, and sunlight to explore solar thermal energy.

Paper Cup Rain water harvesting : Create a rain water harvesting using a paper cups

Paper Cup Whistle : Craft a whistle using a paper cup and investigate the physics of sound production.

Paper Cup Seed Germination Test : Compare different soil types using paper cups to observe seed germination rates.

Paper Cup Lava Lamp : Create a lava lamp using a paper cup, water, oil, and effervescent tablets to study fluid dynamics.

Paper Cup Tornado Tube : Make a tornado tube using paper cups to simulate vortex formation.

Paper Cup Solar Clock : Build a sundial using a paper cup and explore solar timekeeping.

Paper Cup Chromatography : Perform chromatography using paper cups and markers to separate and analyze pigments.

Paper Cup Volcano : Create a paper cup volcano eruption using baking soda and vinegar to study chemical reactions.

Paper Cup Electricity Generator : Generate electricity using a paper cup

Paper Cup Sundial : Craft a sundial using a paper cup and observe how shadows change over time.

Paper Cup Optical Illusion : Create an optical illusion using a paper cup to explore perception and perspective.

Paper Cup Balance Toy : Make a balancing toy using a paper cup and investigate equilibrium.

Paper Cup Hygrometer : Build a hygrometer using a paper cup and a strand of hair to measure humidity.

Paper Cup Solar System Model : Construct a scale model of the solar system using different-sized paper cups to represent planets.

Paper Cup Sound Amplifier : Design a sound amplifier using a paper cup and explore acoustics.

Paper Cup Rainbow Formation : Explore light refraction by filling a paper cup with water and observing rainbow patterns.

Paper Cup Air Cannon : Create an air cannon using a paper cup to study air pressure and propulsion.

Paper Cup Density Column : Layer liquids of different densities in a paper cup to create a stable density column.

Paper Cup Compass : Craft a compass using a paper cup, water, and a magnet to explore magnetic fields.

Paper Cup Simple Machine Model : Build a simple machine model using paper cups to demonstrate mechanical principles.

Paper Cup Water Purifier : Design a water purifier using a paper cup and plastic wrap to remove contaminants.

Paper Cup Kaleidoscope : Construct a kaleidoscope using a paper cup and mirrors to study symmetry and patterns.

These project ideas offer a range of scientific concepts and hands-on activities that you can explore using paper cups. Choose the ones that align with your interests and enjoy your scientific explorations!

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72 Easy Science Experiments Using Materials You Already Have On Hand

Because science doesn’t have to be complicated.

If there is one thing that is guaranteed to get your students excited, it’s a good science experiment! While some experiments require expensive lab equipment or dangerous chemicals, there are plenty of cool projects you can do with regular household items. We’ve rounded up a big collection of easy science experiments that anybody can try, and kids are going to love them!

Easy Chemistry Science Experiments

Easy physics science experiments, easy biology and environmental science experiments, easy engineering experiments and stem challenges.

1. Taste the Rainbow

Teach your students about diffusion while creating a beautiful and tasty rainbow! Tip: Have extra Skittles on hand so your class can eat a few!

Learn more: Skittles Diffusion

2. Crystallize sweet treats

Crystal science experiments teach kids about supersaturated solutions. This one is easy to do at home, and the results are absolutely delicious!

Learn more: Candy Crystals

3. Make a volcano erupt

This classic experiment demonstrates a chemical reaction between baking soda (sodium bicarbonate) and vinegar (acetic acid), which produces carbon dioxide gas, water, and sodium acetate.

Learn more: Best Volcano Experiments

4. Make elephant toothpaste

This fun project uses yeast and a hydrogen peroxide solution to create overflowing “elephant toothpaste.” Tip: Add an extra fun layer by having kids create toothpaste wrappers for plastic bottles.

5. Blow the biggest bubbles you can

Add a few simple ingredients to dish soap solution to create the largest bubbles you’ve ever seen! Kids learn about surface tension as they engineer these bubble-blowing wands.

Learn more: Giant Soap Bubbles

6. Demonstrate the “magic” leakproof bag

All you need is a zip-top plastic bag, sharp pencils, and water to blow your kids’ minds. Once they’re suitably impressed, teach them how the “trick” works by explaining the chemistry of polymers.

Learn more: Leakproof Bag

7. Use apple slices to learn about oxidation

Have students make predictions about what will happen to apple slices when immersed in different liquids, then put those predictions to the test. Have them record their observations.

Learn more: Apple Oxidation

8. Float a marker man

Their eyes will pop out of their heads when you “levitate” a stick figure right off the table! This experiment works due to the insolubility of dry-erase marker ink in water, combined with the lighter density of the ink.

Learn more: Floating Marker Man

9. Discover density with hot and cold water

There are a lot of easy science experiments you can do with density. This one is extremely simple, involving only hot and cold water and food coloring, but the visuals make it appealing and fun.

Learn more: Layered Water

10. Layer more liquids

This density demo is a little more complicated, but the effects are spectacular. Slowly layer liquids like honey, dish soap, water, and rubbing alcohol in a glass. Kids will be amazed when the liquids float one on top of the other like magic (except it is really science).

Learn more: Layered Liquids

11. Grow a carbon sugar snake

Easy science experiments can still have impressive results! This eye-popping chemical reaction demonstration only requires simple supplies like sugar, baking soda, and sand.

Learn more: Carbon Sugar Snake

12. Mix up some slime

Tell kids you’re going to make slime at home, and watch their eyes light up! There are a variety of ways to make slime, so try a few different recipes to find the one you like best.

13. Make homemade bouncy balls

These homemade bouncy balls are easy to make since all you need is glue, food coloring, borax powder, cornstarch, and warm water. You’ll want to store them inside a container like a plastic egg because they will flatten out over time.

Learn more: Make Your Own Bouncy Balls

14. Create eggshell chalk

Eggshells contain calcium, the same material that makes chalk. Grind them up and mix them with flour, water, and food coloring to make your very own sidewalk chalk.

Learn more: Eggshell Chalk

15. Make naked eggs

This is so cool! Use vinegar to dissolve the calcium carbonate in an eggshell to discover the membrane underneath that holds the egg together. Then, use the “naked” egg for another easy science experiment that demonstrates osmosis .

Learn more: Naked Egg Experiment

16. Turn milk into plastic

This sounds a lot more complicated than it is, but don’t be afraid to give it a try. Use simple kitchen supplies to create plastic polymers from plain old milk. Sculpt them into cool shapes when you’re done!

17. Test pH using cabbage

Teach kids about acids and bases without needing pH test strips! Simply boil some red cabbage and use the resulting water to test various substances—acids turn red and bases turn green.

Learn more: Cabbage pH

18. Clean some old coins

Use common household items to make old oxidized coins clean and shiny again in this simple chemistry experiment. Ask kids to predict (hypothesize) which will work best, then expand the learning by doing some research to explain the results.

Learn more: Cleaning Coins

19. Pull an egg into a bottle

This classic easy science experiment never fails to delight. Use the power of air pressure to suck a hard-boiled egg into a jar, no hands required.

Learn more: Egg in a Bottle

20. Blow up a balloon (without blowing)

Chances are good you probably did easy science experiments like this when you were in school. The baking soda and vinegar balloon experiment demonstrates the reactions between acids and bases when you fill a bottle with vinegar and a balloon with baking soda.

21 Assemble a DIY lava lamp

This 1970s trend is back—as an easy science experiment! This activity combines acid-base reactions with density for a totally groovy result.

22. Explore how sugary drinks affect teeth

The calcium content of eggshells makes them a great stand-in for teeth. Use eggs to explore how soda and juice can stain teeth and wear down the enamel. Expand your learning by trying different toothpaste-and-toothbrush combinations to see how effective they are.

Learn more: Sugar and Teeth Experiment

23. Mummify a hot dog

If your kids are fascinated by the Egyptians, they’ll love learning to mummify a hot dog! No need for canopic jars , just grab some baking soda and get started.

24. Extinguish flames with carbon dioxide

This is a fiery twist on acid-base experiments. Light a candle and talk about what fire needs in order to survive. Then, create an acid-base reaction and “pour” the carbon dioxide to extinguish the flame. The CO2 gas acts like a liquid, suffocating the fire.

25. Send secret messages with invisible ink

Turn your kids into secret agents! Write messages with a paintbrush dipped in lemon juice, then hold the paper over a heat source and watch the invisible become visible as oxidation goes to work.

Learn more: Invisible Ink

26. Create dancing popcorn

This is a fun version of the classic baking soda and vinegar experiment, perfect for the younger crowd. The bubbly mixture causes popcorn to dance around in the water.

27. Shoot a soda geyser sky-high

You’ve always wondered if this really works, so it’s time to find out for yourself! Kids will marvel at the chemical reaction that sends diet soda shooting high in the air when Mentos are added.

Learn more: Soda Explosion

28. Send a teabag flying

Hot air rises, and this experiment can prove it! You’ll want to supervise kids with fire, of course. For more safety, try this one outside.

Learn more: Flying Tea Bags

29. Create magic milk

This fun and easy science experiment demonstrates principles related to surface tension, molecular interactions, and fluid dynamics.

Learn more: Magic Milk Experiment

30. Watch the water rise

Learn about Charles’s Law with this simple experiment. As the candle burns, using up oxygen and heating the air in the glass, the water rises as if by magic.

Learn more: Rising Water

31. Learn about capillary action

Kids will be amazed as they watch the colored water move from glass to glass, and you’ll love the easy and inexpensive setup. Gather some water, paper towels, and food coloring to teach the scientific magic of capillary action.

Learn more: Capillary Action

32. Give a balloon a beard

Equally educational and fun, this experiment will teach kids about static electricity using everyday materials. Kids will undoubtedly get a kick out of creating beards on their balloon person!

Learn more: Static Electricity

33. Find your way with a DIY compass

Here’s an old classic that never fails to impress. Magnetize a needle, float it on the water’s surface, and it will always point north.

Learn more: DIY Compass

34. Crush a can using air pressure

Sure, it’s easy to crush a soda can with your bare hands, but what if you could do it without touching it at all? That’s the power of air pressure!

35. Tell time using the sun

While people use clocks or even phones to tell time today, there was a time when a sundial was the best means to do that. Kids will certainly get a kick out of creating their own sundials using everyday materials like cardboard and pencils.

Learn more: Make Your Own Sundial

36. Launch a balloon rocket

Grab balloons, string, straws, and tape, and launch rockets to learn about the laws of motion.

37. Make sparks with steel wool

All you need is steel wool and a 9-volt battery to perform this science demo that’s bound to make their eyes light up! Kids learn about chain reactions, chemical changes, and more.

Learn more: Steel Wool Electricity

38. Levitate a Ping-Pong ball

Kids will get a kick out of this experiment, which is really all about Bernoulli’s principle. You only need plastic bottles, bendy straws, and Ping-Pong balls to make the science magic happen.

39. Whip up a tornado in a bottle

There are plenty of versions of this classic experiment out there, but we love this one because it sparkles! Kids learn about a vortex and what it takes to create one.

Learn more: Tornado in a Bottle

40. Monitor air pressure with a DIY barometer

This simple but effective DIY science project teaches kids about air pressure and meteorology. They’ll have fun tracking and predicting the weather with their very own barometer.

Learn more: DIY Barometer

41. Peer through an ice magnifying glass

Students will certainly get a thrill out of seeing how an everyday object like a piece of ice can be used as a magnifying glass. Be sure to use purified or distilled water since tap water will have impurities in it that will cause distortion.

Learn more: Ice Magnifying Glass

42. String up some sticky ice

Can you lift an ice cube using just a piece of string? This quick experiment teaches you how. Use a little salt to melt the ice and then refreeze the ice with the string attached.

Learn more: Sticky Ice

43. “Flip” a drawing with water

Light refraction causes some really cool effects, and there are multiple easy science experiments you can do with it. This one uses refraction to “flip” a drawing; you can also try the famous “disappearing penny” trick .

Learn more: Light Refraction With Water

44. Color some flowers

We love how simple this project is to re-create since all you’ll need are some white carnations, food coloring, glasses, and water. The end result is just so beautiful!

45. Use glitter to fight germs

Everyone knows that glitter is just like germs—it gets everywhere and is so hard to get rid of! Use that to your advantage and show kids how soap fights glitter and germs.

Learn more: Glitter Germs

46. Re-create the water cycle in a bag

You can do so many easy science experiments with a simple zip-top bag. Fill one partway with water and set it on a sunny windowsill to see how the water evaporates up and eventually “rains” down.

Learn more: Water Cycle

47. Learn about plant transpiration

Your backyard is a terrific place for easy science experiments. Grab a plastic bag and rubber band to learn how plants get rid of excess water they don’t need, a process known as transpiration.

Learn more: Plant Transpiration

48. Clean up an oil spill

Before conducting this experiment, teach your students about engineers who solve environmental problems like oil spills. Then, have your students use provided materials to clean the oil spill from their oceans.

Learn more: Oil Spill

49. Construct a pair of model lungs

Kids get a better understanding of the respiratory system when they build model lungs using a plastic water bottle and some balloons. You can modify the experiment to demonstrate the effects of smoking too.

Learn more: Model Lungs

50. Experiment with limestone rocks

Kids  love to collect rocks, and there are plenty of easy science experiments you can do with them. In this one, pour vinegar over a rock to see if it bubbles. If it does, you’ve found limestone!

Learn more: Limestone Experiments

51. Turn a bottle into a rain gauge

All you need is a plastic bottle, a ruler, and a permanent marker to make your own rain gauge. Monitor your measurements and see how they stack up against meteorology reports in your area.

Learn more: DIY Rain Gauge

52. Build up towel mountains

This clever demonstration helps kids understand how some landforms are created. Use layers of towels to represent rock layers and boxes for continents. Then pu-u-u-sh and see what happens!

Learn more: Towel Mountains

53. Take a play dough core sample

Learn about the layers of the earth by building them out of Play-Doh, then take a core sample with a straw. ( Love Play-Doh? Get more learning ideas here. )

Learn more: Play Dough Core Sampling

54. Project the stars on your ceiling

Use the video lesson in the link below to learn why stars are only visible at night. Then create a DIY star projector to explore the concept hands-on.

Learn more: DIY Star Projector

55. Make it rain

Use shaving cream and food coloring to simulate clouds and rain. This is an easy science experiment little ones will beg to do over and over.

Learn more: Shaving Cream Rain

56. Blow up your fingerprint

This is such a cool (and easy!) way to look at fingerprint patterns. Inflate a balloon a bit, use some ink to put a fingerprint on it, then blow it up big to see your fingerprint in detail.

57. Snack on a DNA model

Twizzlers, gumdrops, and a few toothpicks are all you need to make this super-fun (and yummy!) DNA model.

Learn more: Edible DNA Model

58. Dissect a flower

Take a nature walk and find a flower or two. Then bring them home and take them apart to discover all the different parts of flowers.

59. Craft smartphone speakers

No Bluetooth speaker? No problem! Put together your own from paper cups and toilet paper tubes.

Learn more: Smartphone Speakers

60. Race a balloon-powered car

Kids will be amazed when they learn they can put together this awesome racer using cardboard and bottle-cap wheels. The balloon-powered “engine” is so much fun too.

Learn more: Balloon-Powered Car

61. Build a Ferris wheel

You’ve probably ridden on a Ferris wheel, but can you build one? Stock up on wood craft sticks and find out! Play around with different designs to see which one works best.

Learn more: Craft Stick Ferris Wheel

62. Design a phone stand

There are lots of ways to craft a DIY phone stand, which makes this a perfect creative-thinking STEM challenge.

63. Conduct an egg drop

Put all their engineering skills to the test with an egg drop! Challenge kids to build a container from stuff they find around the house that will protect an egg from a long fall (this is especially fun to do from upper-story windows).

Learn more: Egg Drop Challenge Ideas

64. Engineer a drinking-straw roller coaster

STEM challenges are always a hit with kids. We love this one, which only requires basic supplies like drinking straws.

Learn more: Straw Roller Coaster

65. Build a solar oven

Explore the power of the sun when you build your own solar ovens and use them to cook some yummy treats. This experiment takes a little more time and effort, but the results are always impressive. The link below has complete instructions.

Learn more: Solar Oven

66. Build a Da Vinci bridge

There are plenty of bridge-building experiments out there, but this one is unique. It’s inspired by Leonardo da Vinci’s 500-year-old self-supporting wooden bridge. Learn how to build it at the link, and expand your learning by exploring more about Da Vinci himself.

Learn more: Da Vinci Bridge

67. Step through an index card

This is one easy science experiment that never fails to astonish. With carefully placed scissor cuts on an index card, you can make a loop large enough to fit a (small) human body through! Kids will be wowed as they learn about surface area.

68. Stand on a pile of paper cups

Combine physics and engineering and challenge kids to create a paper cup structure that can support their weight. This is a cool project for aspiring architects.

Learn more: Paper Cup Stack

69. Test out parachutes

Gather a variety of materials (try tissues, handkerchiefs, plastic bags, etc.) and see which ones make the best parachutes. You can also find out how they’re affected by windy days or find out which ones work in the rain.

Learn more: Parachute Drop

70. Recycle newspapers into an engineering challenge

It’s amazing how a stack of newspapers can spark such creative engineering. Challenge kids to build a tower, support a book, or even build a chair using only newspaper and tape!

Learn more: Newspaper STEM Challenge

71. Use rubber bands to sound out acoustics

Explore the ways that sound waves are affected by what’s around them using a simple rubber band “guitar.” (Kids absolutely love playing with these!)

Learn more: Rubber Band Guitar

72. Assemble a better umbrella

Challenge students to engineer the best possible umbrella from various household supplies. Encourage them to plan, draw blueprints, and test their creations using the scientific method.

Learn more: Umbrella STEM Challenge

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Walking Water Rainbow Science Experiment

Let’s make a walking water rainbow! There’s no better way for little scientists to learn about capillary action and color mixing than by making water walk (yes – walk!) in this colorful rainbow science experiment. This science experiment is a favorite of ours because it’s so easy to set up and the results are almost immediate.

Check out the simple step-by-step below and then gra b 30 more jaw-dropping (but easy prep!) science experiments kids will love from our shop!

Getting Ready

To prep, I gathered our supplies:

• 6 wide-mouth glasses or jars
• Paper towels (use the kind where you can select a size)
• Food dye or liquid water colors (red, yellow, and blue)

I grabbed the six small glasses first .  We’ve had success using wide-mouth drinking cups and canning jars, too.  Even though they all worked, just remember that bigger glasses will need more food coloring.

I ripped off six sheets of paper towel and folded each sheet in thirds, lengthwise.

We were using pretty small glasses, so I cut a few inches off the folded paper towel so it would fit in the glasses.

It’s a good idea to test your paper towel strip to make sure they fit properly in your glasses.  They should be able to go from the bottom of one jar to the next without sticking up in the air too much. The paper towel on the left shows the just-right height.  It’s important to set up this rainbow science experiment for success!

Making a Rainbow

This colorful rainbow science experiment is so simple and quick, it’s perfect for even the youngest little scientists.  My 3 year old, Q, couldn’t wait to get started.

First, I had him line up the glasses and fill the first one with a good squirt of red watercolor , the third with yellow, and the fifth glass with blue.  We left the other glasses empty.

Next, I helped Q add water to the glasses with color until the colored water almost reached the top.

We moved the glasses into a circle and added the paper towels .  Starting with the red, we added one end of the paper towel and then put the other end in the empty glass next to it.

We continued around until the last paper towel was placed into the red glass.

We saw the color wick up the paper towel right away.  This rainbow science experiment doesn’t take long to get going!

After another several minutes, the colored water had almost travelled the whole length of each paper towel.

Five minutes later, the water had traveled all the way up and then down the paper towel and was dripping into the empty glass.

The yellow and red water dripped into the empty cup to make orange!  It made for a good lesson on color mixing.

After another five minutes, we could see the water level had dropped in the red, yellow, and blue glasses and rose in the once empty glasses as the water continued to travel from the more full glasses to the less full glasses.

We grabbed a snack and watched our beautiful rainbow science experiment during the next 20 minutes. The water continued to walk from the primary colored glasses to fill the secondary-colored glasses until all the jars were filled equally.

Not Working?

If you aren’t seeing much movement within a few minutes, it may be that you need to add more water to your colored water glasses.  It really needs to be almost at the top for the water to walk quickly.  So try topping off those glasses and seeing if that gets things moving.

If you see the water moving up the paper towel but it seems like it’s taking forever , it may be the type of paper towel you are using.  You want a paper towel that will really hold a lot of water.  We have used Bounty Select-a-Size and Target’s Up and Up Brand Select-a-Size with success.

It really is worth the extra effort of trying different cups and paper towels to get this activity to work.  And once you have had success, don’t throw out those beautifully-colored paper towels or the colored water!  We gently squeezed out our paper towels and let them dry in a heap on a baking sheet.  We ended up with gorgeous tie-dyed looking paper towels to use for crafts and we used the leftover water as watercolors for painting with later.

The Science Behind It

This rainbow science experiment is as magic as the science behind it.  The colored water travels up the paper towel by a process called capillary action . Capillary action is the ability of a liquid to flow upward, against gravity, in narrow spaces.  This is the same thing that helps water climb from a plant’s roots to the leaves in the tree tops.

Paper towels, and all paper products, are made from fibers found in plants called cellulose .  In this demonstration, the water flowed upwards through the tiny gaps between the cellulose fibers.  The gaps in the towel acted like capillary tubes, pulling the water upwards.

The water is able to defy gravity as it travels upward due to the attractive forces between the water and the cellulose fibers.

The water molecules tend to cling to the cellulose fibers in the paper towel.  This is called adhesion .

The water molecules are also attracted to each other and stick close together, a process called cohesion .  So, as the water slowly moves up the tiny gaps in the paper towel fibers, the cohesive forces help to draw more water upwards.

At some point, the adhesive forces between the water and cellulose and the cohesive forces between the water molecules will be overcome by the gravitational forces on the weight of the water in the paper towel.  

When that happens, the water will not travel up the paper towel anymore. That is why it helps to shorten the length that colored water has to travel by making sure your paper towel isn’t too tall and making sure you fill your colored liquid to the top of the glass.

Rainbow Science Activity Extensions

Turn this demonstration into a true experiment by varying the water level (volume) you start with and seeing how long it takes the water to reach the empty glass.

Or start with the same volume of colored water and change the brand, type (single vs double ply, quilted vs not) or length of paper towel to see how long it takes for the water to “walk” to the empty glass.

You could even use the same volume of water, same length and brand of paper towel but vary the height of the filled glass , by raising them up on books, to see how that affects the speed of the water as it “walks” to the empty glass.

Have you had enough fun with the paper towels?  Try using other paper products to see how the type of paper effects the results.  Try toilet paper, printer paper, newspaper or a page from a glossy magazine.  What do you predict will happen?

Grab a Record Sheet

Help kids keep track of their results by grabbing our free record sheet! Then grab 30 more jaw-dropping (but easy prep!) science experiments kids will love from our shop!

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Rainbow Walking Water Science Experiment for Kids

This walking water science experiment is so much fun and super easy to do! My kids absolutely loved it! It even comes with free printable recording sheets for kids as young as preschool! Check out the video to see how easy this walking water experiment really is. This rainbow activity is perfect for spring science!

Walking Water Science Experiment

Ok, this might just be our favorite science experiment! The whole family (adults included) were completely mesmerized with process. We all couldn’t believe how quickly the water traveled up the paper towel and neat it was to watch the colors mix together.

We have wanted to try it out for a long time now and I am kicking myself for waiting so long. I don’t know why, but I thought it might be difficult to do or take a long time. I was way wrong. It was very easy and we started seeing results right away!

Related: Simple Spring Science and STEAM Activities

The walking water science experiment is great at any time of the year, but it is especially perfect for spring. I love doing rainbow activities in the spring, so this was a great addition to our rainbow theme activities.

If you are looking for simple science to do with the kids and something that will really WOW them, this is definitely one to try.

You only need a few simple supplies that you probably already have around the house.

Setting Up the Rainbow Science Experiment

Supplies Needed:

• Printable walking water recording sheets (button to download at the bottom of the post)
• Small plastic cups or glasses
• Paper towels (*read my tips below for picking the right ones)
• Food coloring in primary colors

* The pick-a-size paper towels are best because then you just use half sheets for each cup. If you only have full sheets, then cut them in half. I’ve also heard that more absorbent paper towels work better too. I buy the cheap store brand ones, and our water moved pretty quickly from cup to cup, so I am not sure how important that is. It may have went quicker with something more absorbent though.

1. Print out the recording sheets and make copies, if needed.

2. Place 7 cups in a row and pour water in the 1st, 3rd, 5th, and 7th cup. My cups were about 3/4 full. I have since heard that fuller is better.

3. Add 5 drops of red food coloring to the 1st cup and the 7th cup.

4. Add 5 drops of yellow food coloring to the 3rd cup.

5. Add 5 drops of blue food coloring to the 5th cup.

Doing the Walking Water Experiment

You want to try to use the same amount of food coloring in each cup. When I did this with my kids they did drop an extra one or two in since they can’t control it well, but I just added a drop or two more to the others to even it out.

6. Take a half sheet of paper towel and fold it in half lengthwise and in half again lengthwise.

7. Trim off some of the length so that there isn’t too much excess paper towel that will stick up in the air between each cup. This will make the water walk more quickly.

8. Place one half of a rolled paper towel in the 1st cup and place the other half in the cup next to it. Then another paper towel from 2nd cup and into the 3rd cup. This continues until you have placed the last paper towel that drapes over from the 6th cup to the 7th cup.

9. Stare at the cups and watch what starts happening. You should quickly be able to see the colored water begin to crawl up the paper towel.

10. Don’t forget to do the first part of the recording sheet. Students will predict what they think will happen.

This walking water experiment is AWESOME!

Keep checking back every couple of minutes. Soon you will be able to see that the water has crawled all the way up the paper towel and is beginning to walk back down into the empty cup next to it.

Since the cup on either side of an empty cup has colored water in it, the two colors begin to mix in the empty cup. So cool!

Keep coming back throughout the two hours or soon and observe what is happening.

Question to Ask

What do you think will happen to the water?

What is happening now?

Why do you think the colors are changing?

Why might the water be able to move up against gravity like that?

How this Science Experiment Works

The water moves up the paper towels through a process called capillary action. The paper towel is made from fibers and the water is able to travel through the gaps in the fibers. The gaps in the paper towel act like capillary tubes and pull the water upward. This is what helps water climb from a plant’s roots to the leaves at the top of the plant or tree.

The water is able to move upward against gravity because of the attractive forces between the water and the fibers in the paper towel.

I even removed one of the red cups and made a color wheel so I could introduce the kids to that as well.

I hope your kids have a great time with this super cool walking water science experiment!

Other Cool Science Experiments for Kids

This rainbow  Walking Water Science Experiment  is one of our most popular science activities!

Try this super simple  Oobleck recipe  that only requires two household ingredients!

This  rainbow skittles experiment  is sure to WOW the kids!

You can also make a rainbow of flowers with this super cool  color changing flowers experiment !

This pepper and soap experiment is very simple to do, but always engages the kids!

Did you know you can put paper under water and it will stay dry? Give it a try with this keep paper dry under water experiment . The kids love this cool trick!

Explore Newton’s color wheel while making colors disappear with this totally awesome science activity!

Explore chromatogography with this super fun STEAM activity that combines science and art!

This  rain cloud jar science experiment  give children a chance to explore clouds and rain in a hands-on and engaging way

The kids will get a kick out of this super cool  dancing raisins science experiment !

Check out these other science experiments and activities for kids.

This lava lamp science experiment is always a hit with the kids!

If you haven’t tried this magic milk science activity , you have to! It is so awesome and super easy to do.

This leak proof bag science experiment will make your kids jaw drop! It’s hard to believe, but it works.

Make a Paper Cup Phone

January 31, 2019 by OneMommy

It seems everywhere you look people are talking about STEM activities for kids .   Not only do the activities get kids thinking about science, technology, engineering, and math, but kids genuinely love STEM challenges .

This week we had fun with a classic STEM activity : making a paper cup phone , something I remember doing as a child.

Affiliate links have been provided below. See my full disclosure here . 

Making a cup phone is a fun way to learn about the science of sound.  You might also want to try this simple sound experiment .

Paper Cup Phone

Materials Needed: 

• 2 paper cups
• 20 feet of string (We used yarn.)
• Sharpened Pencil
• 2 Paper clips (optional)

To make your own cup phones, use the tip of a pencil to poke a small hole at the bottom of each of your two cups.

Next, thread the string through the hole of one cup.  We just tied a knot in the yarn on the inside of the cup to keep it in place.  If the string keeps slipping through the hole you can tie it to a paper clip to help keep it in place.

Pull the string through the bottom of your second cup, securing it with an knot on the inside, too.  (See photo above.)

To use your cup phones the string must be kept taut.  When one person whispers in their cup, the other should be able to hear their voice through their own cup.

My daughter was thrilled to hear my voice being whispered in her ear from over 20 feet away!

You can even try whisper singing into the cup, turning it into a musical STEM activity .  

Related post: STEM Challenge: Build a Boat that Floats

Why does the string and paper cup phone work?

Sound waves can travel through air, solids, and liquids.

When you speak into the cup, the vibrations are transmitted into the string.  They continue to travel through the string, as long as it is held taut, to the receiving cup.  There the vibrations are transmitted to the air in the cup, around the listener’s ear, allowing the whisper to be heard.

Because the cup and string are solid, and solids actually carry sound waves better than air, the whisper can be heard much clearer than if you were to just whisper into the air from that distance.

Take your cup phone activity further!

Have your child try one or more of the following extension activities:

• Use a longer piece of string.  Does the homemade phone still work if the string is 40 feet?  How about 60?
• Try making the phone with plastic cups or tin cans.  Which phone works the best?
• Replace the string with wire.  How does this affect the phone?

You kids will have fun learning how to make a paper cup phone! 

You may also like:

• Music STEM 
• STEM Challenge: Design a Boat that Floats
• STEM Challenge: Craft Stick Catapults
• STEM Challenge: Build a Stuffed Animal Chair
• Old-Fashion Fun with Tin Can Stilts

Join our newsletter and get fun activities delivered to your email twice a month.

March 1, 2015 at 4:12 pm

That was one of my fav things to do as a kid! I would use one to go form my neighbors house to mine. I would use it also from the top bunk bed to the bottom for fun lol!

OneMommy says

March 3, 2015 at 11:04 pm

I love the idea of going from bunk bed to bunk or to a neighbor’s house! We need to use a longer piece of yarn!

susen @Dabbling Momma says

March 1, 2015 at 10:20 pm

fun!! Gonna give it a try.

March 2, 2015 at 1:38 pm

It is definitely old school. Now, I have to head your way to check out that Dr. Seuss CVC word hunt!

March 2, 2015 at 1:37 pm

It is such a classic. Now, I see your last post was Dr. Seuss related, so I am definitely heading over to check it out! 🙂

March 3, 2015 at 12:06 pm

Ah, this takes me back. When I was little my best friend/next door neighbour and I would make these and talk from our bathroom window to her bedroom window and think how clever we were! It was about 15 foot and we could just as easily shout but this was WAY more fun!

[…] of; it's actually one of those science activities which completely blows my mind! And I love this paper cup telephone activity, always amusing for children to […]

[…] Make a string cup phone […]

[…] How to make a Paper Cup Phone –  […]

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Science Experiments

Color Changing Walking Water Science Experiment

Science or magic? This super quick, gravity defying experiment may surprise young scientists and work like magic, but don’t worry! The color changing walking water experiment is science through and through and fun for all ages.

Based on the very popular Walking Water Science Experiment using two glasses, you can observe the water walking AND changing color with only a few supplies you probably already have in your kitchen. This article includes a video to show you just how easy it is with detailed step-by-step instructions and the scientific explanations you need to understand how it works!

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

Supplies Needed

• 3 Glasses of Equal Height
• Paper Towels
• Food Coloring (Blue & Yellow)

Color Changing Walking Water Science Lab Kit – Only $5

Use our easy Color Changing Walking 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!

Color Changing Walking Water Science Experiment Instructions

Step 1 –  Prepare two strips of paper towel between 1 and 2 inches wide. Tip: We used one section of paper towel and folded it in half and then in half again until it was the correct width. Set the paper towel strips aside and gather the rest of the supplies

Step 2 – Next, Position your three empty glasses about 2-3 inches apart. Pour water into the two outside glasses until they are halfway full. Leave the middle glass empty.

Step 3 – Add a few drops of food coloring to the water. Add blue food coloring to one glass and yellow food coloring to the other glass. Stir the water until the food coloring is fully combined.

Helpful Tip: If you don’t have blue & yellow food coloring, you can use red & yellow or red & blue. 

Step 4 – Take one of the strips of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the blue water. Then place the other end into the glass that is empty.

Step 5 –  Take the other strip of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the yellow water. Then place the other end into the glass that is empty.

Take a moment to make some observations. What happened to the paper towel that was placed in the water? Do you think it is possible for the water in the first glass to move to the empty glass? What do you think will happen if the water moves to the middle glass? Write down your hypothesis (prediction) and then leave the glasses to sit and come back to check on them in about an hour.

Step 6 – Return to the glasses and observe what has happened. What happened during the hour you were waiting? What do you think will happen if you wait a little longer. Do you think all the water in the outside glasses will move to the middle glass? Why or why not? Write down your hypothesis (prediction) and then leave the glasses to sit and come back to check on them in two hours.

Color Changing Walking water Science Experiment Video Tutorial

How Does the Experiment Work?

Why Does the Water Move Between Glasses? The water appears to defy gravity, but in reality, it moves because of a process called capillary action . Water is able to move against the force of gravity because water molecules stick to each other AND they stick to the fibers of the paper towel. As water molecules are attracted to the fibers of the paper towel, they pull other water molecules with them. The adhesive forces between the water and the fibers of the paper towel are stronger than the cohesive forces between the water molecules. This allows water to travel from one cup to another.

Capillary action is the combined force of attraction among water molecules and with the molecules of surrounding materials.

Why Does Water Change Color? Did you know that three basic colors can combine together to make any other color? These three basic colors are red, blue and yellow. They are referred to as primary colors. When two primary colors combine in equal amounts, they produce a secondary color. In this experiment, we chose blue and yellow (two primary colors) for the outside glasses. When the blue and yellow water mixed in the middle glass it turned green (a secondary color).

More Science Fun

Eventually, the water will stop moving over once both cups are filled with the same amount of water. Expand on the experiment, by estimating how long it will take for the water to move to the second jar. Then set a timer and find out how close your estimate was.

You can also try this experiment with other colors!

Red + Yellow = Orange Red + Blue = Purple

In addition, you can also try these other fun experiments that contain mixing colors:

• Coloring Changing Water Science Experiment – Science or magic? Try this experiment at home with your kids and watch their eyes light up as you pour the liquid into the bowl and “create” a new color.
• Discover How Colors are Made   – This is a simple experiment that demonstrates how different colors are made.

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

Instructions

• Prepare two strips of paper towel between 1 and 2 inches wide. Tip: We used one section of paper towel and folded it in half and then in half again until it was the correct width.
• Once you have your two paper towel strips ready, set them aside.
• Next, Position your three empty glasses about 2-3 inches apart.
• Pour water into the two outside glasses until they are halfway full. Leave the middle glass empty.
• Add a few drops of food coloring into the water. Stir the food coloring until the water is all one color. Tip: Use blue food coloring in one glass and yellow in the other.
• Take one of the strips of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the blue water. Then place the other end into the glass that is empty.
• Take the other strip of paper towel that you prepared in step 1. Place one end of the paper towel into the glass with the yellow water. Then place the other end into the glass that is empty.
• Observe the experiment right away. Do you notice that the water is “walking” up the paper towel? Now, leave the glasses alone and come back to check on them in an hour or two.
• Return to the glasses and observe what has happened.Tip: The longer you wait to check on the glasses, the more water will have moved to the middle glass. The water will stop moving over when all of the cups are filled with the same amount of water.

Reader Interactions

December 26, 2016 at 5:57 am

I want many science experiments for my kids.Thanks for your sharing.

December 10, 2019 at 7:33 pm

Thank you because I really needed something to do for my science fair and now i’m good to go

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Science project, boiling water in a paper cup.

Were humans able to boil water before we discovered how to make metal cookware? Absolutely. We’ve been boiling water in large, cup-shaped leaves for thousands of years! We’re able to pull this off because of a process called conduction, whereby heat is conducted away from the leaf and into the water. Do you think it’s possible to accomplish the same thing with a paper cup?

Is it possible to boil water in a paper cup? Why or why not?

• Several plain paper cups—most are coated with wax, but try to find the uncoated kind
• Several Styrofoam cups
• Stove burner
• Large cabbage (optional)
• Turn the burner on medium heat.
• Fill a paper cup nearly to the brim with water.
• Using tongs, hold the cup of water about six inches above the heating element.
• Continue holding the cup over the heat. The paper or burn, or the water will boil. Record your observations. How can you explain what you saw happen?

• Fill another paper cup with sand.
• Repeat Steps 3 and 4 with the cup filled with sand and record your observations. Did the cup filled with sand produce a different result? If so, why?
• Fill the Styrofoam cup with water.
• Repeat Steps 3 and 4 with the Styrofoam cup and record your observations.

Extra: Repeat steps 3 and 4 with a large cabbage leaf filled with water. What happens?

Boiling water in a paper cup isn't as hard as it looks! If you held the cup at an appropriate distance from the flame, the water in the paper should have eventually boiled. The circular rim on the bottom may have burned. If your paper cup had a waxy coating, the wax may have melted off. The paper cup with sand will burn slightly. The Styrofoam cup will disintegrate.

Water draws heat away from a heat source through convection until it reaches its boiling point of 100 degrees Celsius. The temperature of the water remains fairly constant once it starts boiling—in fact, liquid water is incapable of getting hotter until it’s all turned to steam. Most types of paper burn at 233 degrees Celsius (or 451 degrees Fahrenheit). As the water heats up, it conducts heat away from the paper, preventing the paper from reaching that crucial temperature. Heat also continues escaping via the steam that’s created when water boils.

Sand also has the ability to conduct heat away from the paper, but it also has the potential to get a whole lot hotter than water. Eventually, the temperature of the sand climbs past 100 degrees Celsius, and once the temperature approaches 233 degrees Celsius, the paper will burn.

Styrofoam is an insulator, making it very poor at conducting heat. Heat can’t pass on through to the water, so the Styrofoam disintegrates.

Now go ahead and bet a friend or family member that you can boil water in a Styrofoam cup.  Then do it!  Here's how:

• Find a clean, dry rock small enough to fit in the cup without touching the sides.
• Fill the Styrofoam cup about two-thirds full of water.
• Using tongs, hold the rock directly over the flame until the rock glows orange.
• Using tongs, immerse the rock into the cup WITHOUT letting it touch the sides of the cup.  The water in the cup will boil.

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Bookmark this to easily find it later. Then send your curated collection to your children, or put together your own custom lesson plan.

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How Does a Paper Cup Phone Work?

Music Experiments for Kids

A simple paper cup phone works by transmitting sound vibrations along a tightly-pulled string. The bottom of each cup serves as a combination "microphone" and "speaker," picking up sound vibrations on one and and reproducing the sound at the other. The phone is easy to make from inexpensive materials you can find around your home or buy at a grocery or hardware store, and teaches basic ideas about the science of sound and vibrations.

Making a Paper Cup Phone

A paper cup phone requires two cups, a length of inelastic string, thread or fishing line, two paper clips and a pencil or sewing needle. To create a paper cup phone, poke a hole in the bottom of each of the cups with the pencil or sewing needle and thread each end of the string through each hole. Tie each end of the string to a paper clip to prevent the string from detaching from the cups. Pull the string taut and have one person speak into one of the cups while you listen through the other. The cups can be used to communicate over distances of up to 100 feet.

Sound Transmission

The paper cup phone is a popular science experiment due to how well it illustrates the mechanics of sound transmission. Sound requires a source to vibrate at an audible frequency (generally between 20 Hz and 20 kHz). These vibrations travel through any solid, liquid or gaseous medium as longitudinal waves. Though sound waves can travel through air, solid and liquid mediums transmit sound more effectively, due to their greater density.

Speaking into the cup transmits the sound of the speaker’s voice into the bottom of the cup. The bottom of the cup acts as a diaphragm and vibrates with the sound of the speaker’s voice. As the bottom of the cup vibrates, it transmits the vibrations into the taut string. The sound travels along the string as a longitudinal wave and ultimately vibrates the bottom of the receiving cup. The cup transmits the sound into the air around the listener’s ear, allowing her to hear the speaker. Because the sound travels through solid mediums – the cup and the string – it travels more effectively than through air, allowing the users to communicate across large distances with volumes that would be inaudible if spoken through air.

Effective Cup Phones

You must pull the string taut in order for the phone to work. Longitudinal waves travel through a medium by a process of compression and rarefaction, which in this case alters the tension of the string. If the string is loose, the alterations in tension won't vibrate the listener’s cup. Similarly, elastic string won't work properly, because the wave will just stretch the string without vibrating the listener’s cup.

Don't let the string come into contact with any other objects, as this will weaken the signal on the receiving end.

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• Michigan Reach Out: String It Along
• Scientific American: Talk through a String Telephone

About the Author

Based in New Mexico, Carlos Soto has written video gaming and technology articles since 2005. His writing has appeared on popular websites such as GameFAQs and Destructoid. He earned a Bachelor of Fine Arts in dramatic writing from New York University.

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Science Fun

Dry Paper Magic Science Experiment

In this fun and easy magic science experiment for kids, we’re going to see if we can put paper in water and keep it dry. 

• Piece of newspaper
• Sink or large bowl full of water

Instructions:

• Crumple a sheet of newspaper up in a ball.
• Push the ball of newspaper into the bottom of the glass tightly so it does not fall out when turned upside down.
• Turn the glass upside down.
• Hold the glass by the bottom and push it down into the water so that the glass is fully submerged.
• Remove the glass after several seconds and check to see if the newspaper is wet.

EXPLORE AWESOME SCIENCE EXPERIMENT VIDEOS!

How it Works:

The air pressure around the cup is the same as the air pressure in the cup. When the cup is pushed into the water, the air molecules and the air pressure within it remain and acts as an air cushion. The trapped air acts as a cushion and blocks the water from entering and getting the paper wet. 

Make This A Science Project:

Try different sized cups. Try using a straw or tubing to blow air into an upside down cup that is under water and full of water. 

EXPLORE TONS OF FUN AND EASY SCIENCE EXPERIMENTS!

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May 6, 2011

Talk through a String Telephone

Bring Science Home: Activity 5

By Katherine Harmon

Key concepts Sound Waves Hearing

From National Science Education Standards : Transfer of energy

Introduction Have you ever tried to have a conversation with someone so far away that you couldn't really hear each other? Without yelling, it's hard to have a conversation over long distances. So these days it's nice to be able to use telephones to talk with someone—whether he or she is 100 yards or 100 miles away.

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Back before there were cell phones or even cordless phones, all telephones were hooked up to wires that helped to carry the sound of a person's voice (via an electric signal). And you can use the same concept to build your own telephone using just cups and some string. What message are you going to share over the string?

Background When we talk, our vocal cords make molecules in the air vibrate. (You can feel the vibrations by holding your hand against your throat while you talk.) Those vibrating air molecules make other air molecules around them vibrate, and so on, which is how sound travels through the air. (Different pitches of sound move in waves that have different spacing between them—or "frequency.") Other sources of sound, such as guitar, violin or piano strings are good examples of how vibrations can generate sound.

Inside our ears are tiny sensitive hairs. They pick up the vibrations and transmit that information to our brains, which interpret it as sound. The brain interprets sounds as having different pitches, or tones, based on the frequency, or spacing, of the waves.

But the particles in air are spread out from one another more than particles in a liquid or solid. So sound vibrations tend to peter out before they travel very far. Having a soft connective material, such as cotton string—which has a higher density, or number of molecules in a given amount of space, than air—can help the sound waves move over a greater distance.

Materials •   Two large paper cups (disposable plastic cups will also work) •   Two paperclips or toothpicks •   Length of cotton string or fishing line approximately 10 to 30 feet long •   Quiet area

Preparation •   Punch a small hole in center of the bottom of each cup (for plastic cups, you might need a nail or other sharp tool, so use caution when completing this step). •   Thread one end of string through the bottom of each cup. •   Place a paperclip or toothpick in the bottom of each cup and tie the loose end of the string around it (the clip or pick is just here to keep the string from slipping through the bottom of the cup).

Procedure •   Give one cup to your conversation partner and hold one yourself. •   Walk slowly apart until the string connecting the cups is straight and tight. •   Put your cup over your ear and have your partner talk into his or her cup (keep the conversation relatively quiet if you are standing close to one another, but be sure to talk louder than a whisper). •    Can you hear your partner talking? •   Now you try talking into your cup and have your partner listen into his or her cup. Can he or she hear you? •   Try letting the string go slack. Is the cup-and-string telephone still effective? •   Now, keeping your voice at the same level and remaining the same distance apart, try talking to each other without using the cups. Can you hear as well? •    Extra: If you have plenty of space, see how far apart you can get the cup-and-string telephone to work. •    Extra: If you have a third person around, ask them to hold on to the center of the string with their hand. Will the sound still carry through? Why or why not? •    Extra: If you have other materials (such as yarn, fishing line, nylon string, etc.) on hand, try them out. How do different materials change the quality of sound or how far the sound will travel?

Read on for observations, results and more resources.

Observations and results Could you hear your partner better using the cups and tight string than if you were speaking to each other in the same volume over the air?

In this activity, your voice vibrated the air inside of the cup, which in turn made the bottom of the cup vibrate. These vibrations were transferred to the string and then into the bottom of your partner's cup, which made the air inside of his or her cup vibrate and become detectable sound. When the string goes slack, the vibrations dissipate more easily and get lost along the way. (Landline phones work on the same idea but they transfer the sound waves into an electrical signal, which can travel even farther over wires—and the landlines don't have to be kept taut.)

Sound, such as human speech, travels in incredibly small waves—incredibly fast (about 1,126 feet per second), which is why you couldn't see it or detect a delay while it traveled across the cups and string.

Have you ever noticed how things sound different underwater? Because water's molecules are packed together more closely than those in air, sound waves move more easily—faster and farther—under water. Whales and other marine animals that use sound to communicate under water take advantage of this fact. Scientists think whales can hear each other from hundreds (and maybe even thousands) of miles away—without even a string telephone!

Share your string telephone observations and results! Leave a comment below or share your photos and feedback on Scientific American 's Facebook page .

Cleanup Untie or cut the string from the paperclips or toothpicks. Recycle or reuse what materials you can.

More to explore "Ear Cells Actively Amplify Sound" from Scientific American "(Don't) Pump Up the Volume: Sound Waves Silence Whales' Song" from Scientific American "Sound" Activities from The NASA Sci Files "Frequency, Wavelength and Pitch" overview from Connexions Sounds All Around by Wendy Pfeffer, ages 4-8 Janice VanCleave's Physics for Every Kid: 101 easy experiments in motion, heat, light, machines and sound by Janice VanCleave, ages 9-12

Up next… Yeast Alive! Watch Yeast Live and Breathe

What you'll need •   Fresh packet of baker's yeast (check the expiration date) •   Tablespoon of sugar •   Clear plastic bottle with a small opening (such as a water bottle) •    Funnel •   Small balloon •   Warm water

Tin Can & String Telephone: A Simple STEM Experiment

What transmits sound better: recycled soup cans or plastic party cups.

Experimenting with tin can or plastic cup telephones can be a great boredom buster for kids! Kids growing up in the smartphone generation will be amazed at how something as simple as STRING can transmit sound.

Granted, tin can phones aren’t the most practical communication device. Since the line between cans needs to be held taut to transmit sound, you’re unlikely to “place a call” farther than down the hall or across the back yard.

Unless…

Worlds Longest Tin Can Phone

The Guinness Book of World Records says the worlds longest FUNCTIONING tin can phone was made in Japan in August 2019. It went 242.626 meters, or 796 feet! That’s almost three football fields long! Sadly, there’s no details on how the phone was made or what materials they used.

If you want a little inspiration before setting up your own backyard experiment, check out this video from 2013 when a few friends set up a tin can phone between two houses over 650 feet apart! Not only is their experiment amazing, but the video is well made and entertaining.

Lots of YouTubers have tried their own tin can phone experiments. Spoiler alert: the Danocracy might SAY they made the world’s longs phone at 1000 feet …but it didn’t work. Does that make it click bait? ¯\_(ツ)_/¯

Supplies for a String Telephone Experiment

First…I want to point out that “tin cans” these days are actually made of steel. Steel cans are lined with either tin or plastic to prevent rust and keep your food tasty. But we still call them “tin cans” out of habit.

A basic string phone can be made with supplies you’re likely to have around the house. If you want to get really scientific, try out a variety of “receivers” and types of string.

You’ll need two cans or cups. These can be recycled soup cans, plastic party cups or paper cups. The cups will help transmit the sound — keep notes and find out which cup works best!

Note: We found Styrofoam cups to be pretty horrible. The material is too fragile when you pull the string tight. Little kids are likely to rip a hole in them.

You’ll also need string, and lots of it! The guys in the 2013 video used nylon twine, which is pretty stout. Of course they were also running their line over 650 feet. Cotton string, fishing line and ordinary twine also work. What else can you try out? Yarn? Dental floss? Sewing thread?

Make a String Telephone for Kids

Conduct an experiment in SOUND with this old school craft!

• 2 Clean Cans or Disposable Cups
• String (at least 25 feet)
• Washer or Paper Clip (optional)

Instructions

• If using a recycled can, work on a a sturdy surface, like a work bench if you have it or a thick plastic cutting board. (Don't hammer on your nice kitchen table!)

• If using a disposable cup, you should be able to poke a hole in the bottom of the cup without a hammer!
• Repeat for both cans or cups. You'll need two!

• Pull the string through the can. Tie a large knot in the string. It needs to be big enough to prevent the string from coming out.
• If your hole is too big, or the string too narrow, tie the string to a washer or paper clip to keep it in place.
• Repeat for the other can or cup.

If you're running this as an experiment, make several phones at once with a variety of materials. You can also try a can on one end and a cup on the other. Which work best? Record your results!

How to Use Tin Can or Cup Telephones

Once you’ve made your telephone, you’ll need two people to run the experiment. Have each person take an end and walk apart until the string is TIGHT. One person then holds the can or cup to their ear while the other talks into their can or cup.

Ideally, you’ll want to stand far enough apart that you can speak normally into the phone and not be heard by the other person. If you can’t get THAT far apart, try a whisper!

Pet Peeve: A lot of stock photos (and blogger photos!) of people using tin can phones are misleading. They show people with the string dangling loosely between the two ends. This WILL NOT work. No wonder that guy looks confused.

They also show people standing right on top of each other. You need a bit of distance for this experiment to really work.

Record Your Experiments

Level up your tin cans from “just another craft” to a fun STEM event by making several phones or swapping out materials. Record your results!

How far did you get? How clearly did you hear the words? Which one was easier to make?

Jot down your findings on a scrap of paper, or use the free printable below. You can also record your experiment using a Voice Recorder app on your smart phone for later comparison.

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DIY Phone Speaker

July 2, 2020 By Emma Vanstone Leave a Comment

I can’t promise great sound quality, but this DIY phone speaker will make your phone sound louder and a bit less tinny!

This easy science project is a great for older children and useful too!

You’ll Need

Cardboard tube

2 plastic cups

Phone with a speaker at the bottom

How to make a DIY speaker

Carefully cut a hole in the side of each plastic cup so the cardboard tube fits inside tightly.

Attach a cup to each end of the tube.

Cut a thin slit in the top of the cardboard tube just big enough to hold your phone.

Choose some music and listen to the sound in and out of the speaker.

It should sound louder when the phone is inside the tube.

Why does it work?

When the phone plays music outside the tube the sound spreads out all around, but when you put the phone inside the cardboard tube the sound is directed down the tube towards the plastic cups and out from there! The cups focus the sound waves pointing them in one direction rather than scattered all around.

A megaphone works in a similar way. When a person speaks normally the sound scatters immediately, but a megaphone channels the sound towards the subject instead. This is why people sometimes cup their hands around their mouth to shout! Find out more about megaphones with Wonderopolis.

Print Instructions for DIY iPhone Speaker

Extension tasks for the DIY Phone Speaker

Experiment with different sized tubes and cups to find the best speaker. Does it matter if you use paper cups instead of plastic?

Last Updated on July 2, 2020 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.

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