rainbow in glass experiment

How To Make a Rainbow in a Glass

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• Ph.D., Biomedical Sciences, University of Tennessee at Knoxville
• B.A., Physics and Mathematics, Hastings College

You don't have to use lots of different chemicals to make a colorful density column. This project uses colored sugar solutions made at different concentrations . The solutions will form layers, from least dense, on top, to most dense (concentrated) at the bottom of the glass.

Difficulty: Easy

Time Required: minutes

What You Need

• Food coloring
• 5 glasses or clear plastic cups

The Process

• Line up five glasses. Add 1 tablespoon (15 g) of sugar to the first glass, 2 tablespoons (30 g) of sugar to the second glass, 3 tablespoons of sugar (45 g) to the third glass, and 4 tablespoons of sugar (60 g) to the fourth glass. The fifth glass remains empty.
• Add 3 tablespoons (45 ml) of water to each of the first 4 glasses. Stir each solution. If the sugar does not dissolve in any of the four glasses, then add one more tablespoon (15 ml) of water to each of the four glasses.
• Add 2-3 drops of red food coloring to the first glass , yellow food coloring to the second glass, green food coloring to the third glass, and blue food coloring to the fourth glass. Stir each solution.
• Now let's make a rainbow using the different density solutions. Fill the last glass about one-fourth full of the blue sugar solution.
• Carefully layer some green sugar solution above the blue liquid. Do this by putting a spoon in the glass, just above the blue layer, and pouring the green solution slowly over the back of the spoon. If you do this right, you won't disturb the blue solution much at all. Add green solution until the glass is about half full.
• Now layer the yellow solution above the green liquid, using the back of the spoon. Fill the glass to three-quarters full.
• Finally, layer the red solution above the yellow liquid. Fill the glass the rest of the way.

Safety and Tips

• The sugar solutions are miscible , or mixable, so the colors will bleed into each other and eventually mix.
• If you stir the rainbow, what will happen? Because this density column is made with different concentrations of the same chemical (sugar or sucrose), stirring would mix the solution. It would not un-mix like you would see with oil and water.
• Try to avoid using gel food coloring. It is difficult to mix the gels into the solution.
• If your sugar won't dissolve, an alternative to adding more water is to microwave the solutions for about 30 seconds at a time until the sugar dissolves. If you heat the water, use care to avoid burns.
• If you want to make layers you can drink, try substituting unsweetened soft drink mix for the food coloring, or four flavors of a sweetened mix for the sugar plus coloring.
• Let heated solutions cool before pouring them. You'll avoid burns, plus the liquid will thicken as it cools so the layers won't mix as easily.
• Use a narrow container rather than a wide one to see the colors the best,
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Science Fun

Rainbow in a Glass

• 5 separate cups
• A Tablespoon
• A clear glass
• A dropper or pipette

Instructions:

• Separate the Skittles into the cups, in these amounts: 2 red, 4 orange, 6 yellow, 8 green, and 10 purple.
• Heat a mug of water in the microwave for a minute and a half (or long enough that the water is hot, but not boiling). Be careful removing the water from the microwave–it’s hot!
• Measure and pour two tablespoons of hot water into each cup, on top of the Skittles.
• Stir each cup carefully so no water splashes out. The cups need to be cool for the next part of the experiment, so leave them somewhere where they won’t get knocked over. Stir them every ten minutes or so until the Skittles are dissolved and the water is room temperature.
• Using the dropper, add the colored water from the five cups to the clear glass. Start with purple, then add green, then yellow, orange, and red last. Go slowly here, we don’t want the different layers to mix.
• Congratulations, you made a rainbow. You didn’t even have to go outside!

WATCH THE QUICK AND EASY VIDEO TUTORIAL!

How does it work?

Skittles are mostly made of sugar. When you add hot water to them, the sugar dissolves and the coloring on the shell of the Skittles turns the water different colors. The cup with only two red Skittles doesn’t have as much sugar as the cup with ten purple Skittles, but they both have the same amount of water. The amount of matter packed into a certain amount of space is called the density of the material. The red water is less dense than the purple water, so it will float on top of the purple water.

Further Experiments

• We added our colors in heaviest-to-lightest order. Does the rainbow still form if you add the red water first, then the orange, yellow, green, and purple?
• What happens if you stir your rainbow? What if you leave it sitting there over night?

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Science Experiments

Rainbow in a Jar Science Experiment

Want to make your own rainbow? In this simple science experiment, kids can build their own rainbow in a jar while exploring density, mass, and volume.

Watch our demonstration video, gather your supplies, and print out our detailed instructions to get started. An easy to understand explanation of how it works is included below.

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

Supplies Needed

• Tall Glass Jar
• Food Coloring: Red, Blue and Green
• 1/4 cup Honey
• 1/4 cup Blue Dish Soap
• 1/4 cup Water
• 1/4 cup Olive Oil
• 1/4 cup Rubbing Alcohol
• Jars for mixing and pouring
• Teaspoons for mixing

Rainbow in a Jar Science Lab Kit – Only $5

Use our easy Rainbow in a Jar 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!

Rainbow in a Jar Science ExperimentInstructions

Step 1 – Add one drop of red food coloring and one drop of blue food coloring to 1/4 cup of honey and stir until combined. This creates a purple color liquid. Pour the purple liquid carefully into the tall jar.

Step 2 – Next add about 1/4 cup of blue dish soap to the tall jar.

Step 3 – Add a few drops of green food coloring to 1/4 cup of water and mix until combined. Then, carefully pour the green liquid into the tall jar. Tip: When pouring in the green liquid, tilt the jar so the liquid runs down the side of the jar slowly.

Step 4 – Wait a few moments and then slowly pour 1/4 cup of olive oil into the jar. Again, be very careful when pouring in the liquid. Make sure to tilt the jar and pour very slowly so the colors don’t mix.

Step 5 – Add a few drops of red food coloring to 1/4 cup of rubbing alcohol and mix until combined. Then, carefully pour the red liquid into the tall jar. Tip: I can’t stress enough how important it is to tilt the jar and pour slow. Otherwise, the colors will mix together and you won’t get a distinct rainbow.

Do you know why you were able to make the liquids form the rainbow in a jar? Find out the answer in the how does this experiment work section below.

Video Tutorial

How Does the Science Experiment Work

Density is the reason that this experiment works! Density is a measure of how much mass (or “stuff”) there is in a given volume. Density is a ratio of mass to volume and can be found by dividing an object’s mass by its volume (D=m/v).

Based on this equation, if the mass of something increases but the volume stays constant, then the density increases. Also, if mass decreases but the volume stays constant, then the density decreases. Density is all about how tightly packed the matter making up the material is in a given volume. Lighter liquids (like olive oil and rubbing alcohol) are less dense than heavier liquids (like honey and dish soap) because they have less matter in a given volume. Because olive oil and rubbing alcohol are less dense, they will float on top of liquids like water, dish soap, and honey. Liquids with a lower density will always float on top of liquids with a higher density.

All liquids have their own unique density. Water has a density of 1 g/mL (g/cm3). Objects will float in water if their density is less than 1 g/mL. Objects will sink in water if their density is greater than 1 g/mL.

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

Instructions

• Add one drop of red food coloring and one drop of blue food coloring to 1/4 cup of honey and stir until combined. This is create a purple color liquid. Pour the purple liquid carefully into the tall jar.
• Next add about 1/4 cup of blue dish soap to the tall jar.
• Then add a few drops of green food coloring to 1/4 cup of water and mix until combined. Then carefully pour the green liquid into the tall jar. Tip: When pouring in the green liquid, tilt the jar so the liquid runs down the side of the jar slowly.
• Wait a few moments and then slowly pour 1/4 cup of olive oil into the jar. Tip: Again, be very careful when pouring in the liquid. Make sure to tilt the jar and pour very slowly so the colors don’t mix.
• Add a few drops of red food coloring to 1/4 cup of rubbing alcohol and mix until combined. Then carefully pour the red liquid into the tall jar. Tip: I can’t stress enough how important it is to tilt the jar and pour slow. Otherwise the colors will mix together and you won’t get a distinct rainbow.

Reader Interactions

October 15, 2017 at 3:22 pm

It was cool. Was it density

October 30, 2017 at 11:33 am

Hi it was Cooooolllllll….. It was because of the density

June 12, 2018 at 10:22 am

my kids enjoyed this presentation. They are doing it for a stem project

March 25, 2019 at 3:41 pm

How long did this project take to make and how long did it last until the colors started to mix? Also, what would be the guiding question of an experiment like this?

March 2, 2023 at 11:46 am

1.This experiment took around 20 minutes to put together. 2. It lasts for as long as you need if nobody touches it. 3. A leading question to this experiment could be ” Will all of the ingredients mix while i am pouring?”

I hope this helped:)

January 23, 2020 at 12:41 pm

its amazing my students loved it!

March 2, 2023 at 11:40 am

I did this exact project for the science fair this year and I won 2nd place. I made a full board about destiny and I made a question saying ” If I do not tip the jar or if i pour too fast, will the colors mix? The answer is yes! The colors did mix whenever I didn’t tip the jar and the rubbing alcohol sank down and mixed with the green and then since the extra liquid was in the green it mixed with the blue dish soap and began to be a big bubbly mess! 🙂

June 12, 2023 at 10:15 am

Can you put a top on the jar, shake the jar, mixing the liquids, will the liquids separate after sitting for hours or days?

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• Activities for Kids

6 Incredibly Easy Rainbow Science Experiments

If you can’t find one, make one of your own, right in your kitchen, porch, or stoop

No rainbow in the sky today? No problem. Just pick one (or all) of these easy kid-friendly science experiments with your rainbow-making know-how. From reflection (mirror) to refraction (water glass) to learning about density, we’ve found six science experiments to make or learn from the rainbow. If you want more ideas, check out our sidewalk science ideas or dry ice science experiments .

1. The Mirror Method

Lesson: Demonstrate the principles of reflection and refraction with this easy experiment . Light bending, aka refraction, takes place as light waves pass through the water. When you shine your flashlight (or position your glass so the sun comes in) you are bending the light waves, each one of the waves at slightly different angles resulting in the different colors of the rainbow. This is the same basic principle that occurs when water and sunlight create a rainbow in the sky. Reflection is the light bouncing off of the mirrored surface.

You will need:

A small mirror (like a compact mirror)

A glass of water (big enough to hold the mirror)

A flashlight (or sunlight) 

A piece of white paper or a white wall

1. Put the mirror in the glass of water.

2. Turn off the lights and draw the curtains. Make sure the room is totally dark.

3. Shine the flashlight on the mirror and check out the cool mini-rainbows that appear above the mirror. Put your hand behind the glass for extra fun. 

2. The Garden Hose Technique

Lesson: Refraction, as above. This time, instead of using a mirror to reflect the light, you are going to basically mimic the natural formation of a rainbow by causing the water to hit the light in a fine mist.

A spray bottle or a hose

1. Put the hose on mist or grab your mister and spray it into an area of your yard/house/garden that has natural sunlight hitting it.

2. Let the kids ooh and ahh over your rainbow-making skills, then let each of them take a turn.

3. Water Density Rainbow

Lesson: By adding more or less sugar to each water solution you are creating different density levels. When you add coloring to the glasses you will be able to see which solution is the heaviest. Add the colors in rainbow order to impress the kids. Visit Little Bins for Little Hands for the experiment that shows you how to make a rainbow. 

Food coloring

Five glasses or plastic cups (clear)

4. The Glass o’ Water Approach

Lesson: The most simple form of light bending, this lesson in the light waves is similar to #1 above.

A glass of water

A piece of paper

1. Put the glass of water in the sunlight.

2. Put the paper next to it.

3. Let the sunlight stream through the water and create a rainbow on the paper.

5. Advanced Glass o’ Water Approach:

A spray bottle

1. Put the glass of water on a table or windowsill where there is sunlight.

2. Put the piece of paper on the floor where the sunlight hits, in the line of the glass.

3. Spray the window with warm water where the sun is coming through, and so it lines up with the paper. 

4. Move the glass and paper around until you see a neat little rainbow on the paper.

6. The Bubble Method

It doesn't get any easier than making a rainbow by blowing bubbles. You can use regular dish soap and a bit of water and shake ingredients inside a bottle, or just blow bubbles and observe. Want to up the fun factor? Make your own bubble mixture out of ordinary kitchen ingredients.

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Make a Rainbow in a Jar

Experiment with density as you layer liquids to create a rainbow

• Things to Make
• Experiments

What you’ll need:

• Light-coloured honey
• Dish detergent (either blue or clear)
• Vegetable oil
• Rubbing alcohol
• Food colouring (red, blue, green and yellow)
• Tall, empty jar
• Mixing bowls
• Apron or old clothes
• Gloves (optional)

Note: Food colouring stains, so wear old clothes or an apron. Stains on your fingers will eventually come off.

• Find a jar around your house. The taller your jar, the thicker your layers can be.
• Pour in honey to make the first layer, about 1½ to 2 cm thick. Pour this slowly and evenly into the centre of the jar.
• In a small bowl or glass, combine one drop of red food colouring, one drop of blue food colouring and a few drops of water. Together, they will make purple. Mix the purple water completely into the honey. Let this settle for 60 seconds.
• For your blue layer, use blue dish detergent. Or, if you only have clear dish detergent, put some in a small bowl with a drop of blue food colouring added. Mix it carefully, and then slowly add it to the jar to make a second layer 1½ to 2cm thick.
• In another mixing bowl, add a drop of green food colouring to some water. If you don’t have green food colouring, make your own by mixing blue and yellow together. Tilt the jar, and slowly pour this green water in, so that it trickles down the side of the jar to make yet another layer 1½ to 2 cm thick.
• Wait a few seconds. Then, for your fourth layer, add enough vegetable oil to make a layer 1½ to 2 cm thick. Again, tilt the jar and pour very slowly so the colours don’t mix. (You may be wondering: where’s orange? Sadly, you can’t make this layer truly orange, because water-based food colouring won’t mix with oil.)
• For your top layer, add some red food colouring to some rubbing alcohol. Mix it thoroughly, then tilt the jar and carefully pour it slowly in, until the top layer is 1½ to 2 cm thick.

How does it work?

This rainbow is all thanks to the science of density! Density is a measure of how densely packed molecules are within a liquid. The denser a liquid (for instance, honey), the more closely packed the molecules. Less dense liquids can float on top of more dense liquids because they’re lighter!

Primary Playground

Rainbow In A Jar Science Experiment

February 25, 2018

I love incorporating easy science experiments into the classroom as often as I can. I thought this rainbow in a jar science experiment was perfect for March.

To make this rainbow in a jar, the students are exploring density by layering sugar water to make a rainbow.

The materials are all things you most likely already have on hand.

THIS ACTIVITY WORKS WELL WITH

Approx. 2 cups of warm tap water

1/2 cup measuring cup

1 Tablespoon measuring spoon

4 small jars of glasses

Approx. 1 1/2 cups of granulated white sugar

Red, blue, yellow, and green food coloring

Tall thin glass or test tube. I used an old Starbucks bottle

4 popsicle sticks

Experiment steps

Measure a 1/2 cup of warm tap water into the 4 jars.

Add 2 drops of food coloring to each of the 4 jars.

To the jar of red water, add 2 tablespoons of sugar. To the jar of yellow, add 4 tablespoons of sugar. In the jar of green water, add 6 tablespoons of sugar. And to the jar of blue water, add 8 tablespoons of sugar.

Stir each of the jars to dissolve the sugar. If your water is not warm enough to dissolve the sugar, put the jar in the microwave for 30 seconds at a time, stirring in between until the sugar is dissolved.

The students can already see at this point that by dissolving increasing amounts of sugar, you’re increasing the density of the sugar water solutions. They can easily see that the jars all started the same and now the blue looks a lot fuller than the red.

Step 5: 

Pour about an inch of the blue water into the bottom of your glass or test tube.

Use your straw to gently drip the green water on top of the blue layer. It works best to place the straw to the side of the glass just above the blue layer. You want to add the layers to the glass slowly and carefully, otherwise, they’ll mix together resulting in a muddled rainbow.

Add the yellow layer next using the same method and last the red layer. Stand back and admire your beautiful rainbow!

I hope your students love making the rainbow and learning about density in a fun way!

If you’re looking for another great science experiment that would be great for the science fair, you might like the simple circuit that we made. You can get all of the details for that project here.

See you next time!

Share this:

July 15, 2019 at 2:35 am

I cannot find regular food coloring any where! Can gel food coloring be used??

July 16, 2019 at 1:56 pm

I’ve never used gel food coloring, but if you can get it to mix with the water it would work just fine. Basically, you are just coloring the water in order to be able to see the layers.

November 9, 2019 at 5:05 pm

What a pretty density experiment!!

April 1, 2020 at 7:34 am

I didnt get layers..All the colours got mixed..what could have gone wrong?

April 1, 2020 at 2:50 pm

Hi there. If you didn’t get layers, the sugar measurements may have been off. Also, the layers/colors need to be added VERY slowly otherwise it will all just become mixed. I hope that helps!

April 2, 2020 at 8:17 pm

Would brown sugar work just as well?

April 3, 2020 at 1:48 pm

My guess would be no since brown sugar contains molasses and would be a different density. But it is a science experiment, so it wouldn’t hurt to try it and see what would happen.

April 9, 2020 at 2:55 pm

So fun! It looks awesome! Takes some time to do though but worth it! Kids thought it was cool but I think I had more fun then they did 😁

May 28, 2020 at 10:12 pm

This was extremely fun. First we did not think it was working but then we put a light from behind and seen the wonderful masterpiece. We tried using a straw and it was a bit hard then we found some droppers and it was a whole lot easier. Thank you.

February 26, 2021 at 8:53 pm

I was wondering about the straw and exactly how that would work. With the droppers, did you have to add the drops really slowly and one at a time? Or could you just squeeze it? Asking, because I want to try this with my two and threes. Some will be able to listen and add slowly l, but some may want to squeeze as hard as they can

February 26, 2021 at 9:41 pm

Hi there. If you’re using a straw, you would plug the top end with your thumb and slowly let the liquid run out of it down the side of the inside of the jar. Same for the dropper. You don’t want to just “drop” the liquid in as it will then mix and you won’t get the density layers. You will just end up with a purple, brown mix. It may work for some of your twos and threes, but it may just be too much for some of them. Maybe an alternative is they watch you do it and then they could play with their own droppers in other colored water and make art on paper.

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By Anne Marie Helmenstein, Ph.D.

This experiment takes advantage of density to create a rainbow in a glass. When you add sugar to a liquid, it causes the solution to become more dense. The more sugar you add, the more dense the solution is. If you have different solutions that are all different colors and densities, the colors will layer on top of each other — the denser, more sugary solutions will sit on the bottom and the lightest will sit on the top!  Check it out here >

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Rainbow In A Jar – Science Experiment For Kids

What if you could create your own rainbow in a jar with your little one? Rainbows are beautiful things, aren’t they? But they usually appear only after rain. Did you know a rainbow is formed because of reflection, refraction, and dispersion of sunlight through raindrops? Just after it rains, the sun’s rays bounce off the remaining drops in the atmosphere and split into colors forming a rainbow. But you don’t always wait for it to rain to see a rainbow, you can make one at home with this rainbow in a jar science experiment. 

Download Rainbow In A Jar Printable

All you need is some kitchen chemistry to whip up a beautiful liquid rainbow. The rainbow in a jar experiment is a great way to introduce your child to concepts like volume, density, and viscosity. 

Here is a step-by-step guide to performing this simple experiment in your home:

Things You Need To Make A Rainbow In A Jar 

Steps to set-up the rainbow in a jar experiment, the science behind the rainbow in a jar experiment.

• Other Ways To Make A Rainbow In A Jar?

Conduct An Interactive Session With Your Kid After The Rainbow In The Jar Experiment

Frequently asked questions on rainbow in a jar science experiment.

Here is a list of things you’ll need to perform the rainbow in a jar experiment. All of these are simple and inexpensive things that you can find in your kitchen or pantry.

• A clear, tall glass jar
• 1/4 cup Honey
• 1/4 cup green Dish Soap
• 1/4 cup Water
• 1/4 cup Olive Oil
• 1/4 cup Rubbing Alcohol
• Red, blue and green food coloring
• Jars or bowls for mixing and pouring, and
• Spoons for mixing

Ready to make your own rainbow? Here are the step-by-step instructions to create your own rainbow in a jar. 

• Place the ¼ cup honey in a bowl and add one drop of red food coloring and one drop of blue food coloring to it. Stir well to combine or until the honey becomes purple. Pour purple honey into the tall glass jar.
• Then, measure and pour ¼ cup of green dish soap into the tall glass jar, over the purple honey.
• Next, add a ¼ cup of water with 2 drops of blue food coloring and mix well to combine. Now, tilt the tall glass jar slightly and carefully pour the blue water into the jar. You need to ensure that the water runs down the side of the jar slowly.
• Wait for a few minutes and then pour ¼ cup of olive oil into the tall glass jar. Again, tilt the jar slightly and pour the liquid slowly so that it runs down the side of the jar. This ensures that the colors don’t mix and ruin the rainbow.
• Finally, mix one drop of red food coloring with ¼ cup of rubbing alcohol in a bowl. Stir well to combine and then pour the liquid carefully into the tall glass jar. You need to ensure that you tilt the jar each time when you pour the liquid into the jar to avoid mixing all those beautiful colors. And voila! Your beautiful rainbow in a jar is ready!

Note: If you find it difficult to tilt the jar and pour the liquid, you can use a dropper. Fill the jar using a dropper, but ensure that you pour the liquid slowly along the sides of the jar. And be very careful not to shake the jar at any point, or the colors will mix. This will ensure a beautiful rainbow with distinct colors in the jar.

How did the liquids in the jar stay intact without mixing with each other? The reason why the colored liquids stayed on top of each other without mixing is density! Each of the different liquids that we added into the jar has different densities. This is why the colored liquids stayed in the jar without mixing and thereby forming a beautiful rainbow in a jar.

Honey is the heaviest of all the liquids in the jar, so it sits comfortably at the bottom of the jar. The green dish soap is lighter than honey but heavier than water, so it sits above the honey and below water. The olive oil is lighter than water but heavier than the rubbing alcohol, so it sits between the two liquids. The red-dyed rubbing alcohol is the lightest of the liquids in the jar, so it stays on top. 

Here is a table with the densities of the different liquids in the jar:

What is density?

“Density is the measure of mass per volume” . The heavier density of a substance, the more likely it is to sink. And liquids with lighter densities will float on top. 

Other Ways To Do The Rainbow Science Experiment?

Here are some other ways you can perform the rainbow in a glass experiment.

Rainbow In A Bottle Science Project Using Colored Rice

Try the rainbow in a jar with different colored rice.

Steps To Create A Rainbow In A Bottle Using Colored Rice

• Step 1: Measure and pour ½ cup rice into 5 different bowls.
• Step 2: Add 2 drops of red food color to the 1st bowl, 2 drops of blue food color to the 2nd and 2 drops of green food color to the 3rd bowl. Then add 2 drops of yellow food color to the 4th and 2 drops of orange food color to the 5th bowl. Mix to ensure the rice in each bowl is completely dyed and allow it to dry.
• Step 3: Using a funnel, first fill a tall glass jar or bottle with the red rice. Pour each of the other colored rice into the bottle. Finally, add the orange colored rice on top to finish your rainbow in a jar.

Sugar Syrup Rainbow In A Bottle

Try performing the density experiment for kids with water and sugar. 

Steps To Create A Rainbow In A Bottle With Sugar Syrup

• Step 1: Fill four glasses with ¼ cup of water and add red, blue, yellow and green food coloring. 
• Step 2: Then add 2 tablespoons of sugar to the red liquid and 4 tablespoons of sugar to the blue liquid. 
• Step 3: Add 6 tablespoons of sugar to the yellow liquid and finally, add 8 tablespoons of sugar to the green liquid. Mix till the sugar dissolves. 
• Step 4: Carefully pour each of the colored liquids into a clear mason jar using a dropper, in the order green, yellow, red and blue. You’ll notice that each of the colored liquids stays separate to form a beautiful rainbow in a jar. 

Why don’t the different waters mix in the jar?

Adding an increasing amount of sugar to the same amount of liquid creates several liquids with different densities. So, when they’re poured into the jar, the liquids don’t mix and leave you with a stunning rainbow in the jar.

Why You Should Do The Rainbow In A Jar Science Experiment

When kids learn these science concepts in school, it often remains an abstract concept for little kids. But when you teach the same concept through a science experiment at home, it becomes easier for them to understand. Science experiments for kids at home are fun activities, which help kids connect the textbook knowledge to real-life applications. The rainbow in a jar science experiment is one such activity that will leave your kids in awe. 

Additionally, it’ll help them understand concepts like measurements and the density and viscosity of different liquids. The rainbow in a jar experiment also teaches kids about colors and how mixing two or more colors produces a different color.

The colorful rainbow formed in the jar will leave your child in awe for several hours. Help them understand the science behind the rainbow in a jar experiment by asking them a few leading questions.

Give them a few hints and see if they can arrive at the answer on their own. Then explain the concept of volume and the different densities and viscosity of different liquids to them.

Here is a list of questions to help you get started:

• Why do you think the colors stay intact in the jar without getting mixed?
• Why didn’t the liquids mix in the jar?
• Did you learn anything new from the rainbow in a jar experiment?

What are the things required for the Rainbow In A Jar Science Experiment?

Some of the things required for the Rainbow In A Jar Science Experiment are a glass jar, water, honey, colored soap, oil and rubbing alcohol in equal proportions, blue, red, and green liquid colors and spoons to mix.

What does the Rainbow In A Jar Science Experiment teach children?

The Rainbow In A Jar Science Experiment helps children to understand in-depth concepts of color formation and help them to think creatively about other science experiments. They also improve their decision-making skills.

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How to Make a Rainbow with a Prism

June 21, 2019 By Emma Vanstone Leave a Comment

Visible or white light is made up of a range of colours each with a different wavelength . One way to see the different colours is to use a prism to split the light. When white light enters the prism it slows down and changes direction. The amount the light changes depends on the wavelength. Red light changes direction the least and violet the most.

Visible light is the part of the electromagnetic spectrum we can see. Each colour has a range of wavelengths. Red has a long wavelength and low frequency and violet has a short wavelength and high frequency.

What is a prism?

A prism is a triangular block of glass or perspex which splits light into its constituent colours.

When light enters a prism it is refracted. Each colour of the spectrum is refracted by a different amount and the colours are dispersed ( spread out ) allowing you to see them.

A prism is a great way to demonstrate visually that white light is actually made up of 7 different colours.

How to split white light with a prism

What you need to split light

Triangular prism

White cardboard

Large sheet of white paper

Dark coloured cardboard

Tape or glue

Large tray or sheet of thick card

How to use a prism

If it’s not a sunny day, you can use a torch.

Use the dark card to create a slit over a sheet of white card. Place the card so sunlight shines through giving a thin beam of light.

Place the prism over the light and rotate it until you can see the light split into the spectrum of colours.

Why does a prism split light?

White light, which enters the prism, is a mixture of different wavelengths, which get bent ( refracted ) by different amounts though the prism, allowing them to be seen separately.

Facts about light waves

Light travels in straight lines.

It takes 8 minutes and 20 seconds for light to reach Earth from the Sun.

Light waves can travel through a vacuum.

Visible light is a form of electromagnetic radiation.

Light waves are much faster than sound waves.

Wavelengths of the visible spectrum of light range from 400nm ( violet end ) to 700nm (red end ).

More learning activities about light

Find out how to make a rainbow using a hosepipe !

Reverse the direction of arrows with this easy light refraction experiment .

Learn about how light travels in straight lines by making a light maze .

Last Updated on May 7, 2022 by Emma Vanstone

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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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Science project, rainbow in a jar.

How many times have you peeked out the window on a rainy day and seen a rainbow (or two)? Rainbows usually only appear after the rain because the sun's rays bounce off the drops remaining in the atmosphere. As they do, they split into all the colors of the rainbow.

This resembles what you see when you shine light through a prism. The glass splits the white light up into its different frequencies.

In both cases, you need two things: a source of light, and a transparent substance like glass or water.

But wouldn’t it be spectacular to hold a rainbow in a jar?

How can we use chemicals to make a rainbow in a jar?

• 1/2 cup blue dishwashing liquid
• 1/2 cup olive oil
• 1/2 cup rubbing alcohol
• 1/2 cup light corn syrup
• Food coloring
• 5 bowls for mixing
• Make your purple layer by mixing 1/2 cup of the light corn syrup with 1 drop of blue and 1 drop of red food coloring.
• Carefully pour it into the bottom of your jar.
• Carefully pour the blue dish soap down the side of the jar.
• Mix 1/2 cup of water with 2 drops of green food coloring.
• Carefully pour in your green water down the side of the jar.
• Gently pour 1/2 cup olive oil down the side of your jar.
• Mix 1/2 cup of rubbing alcohol with 2 drops of red food coloring.
• Carefully pour the red rubbing alcohol down the inside of your jar.
• Being careful not to disturb your liquids, set your jar down on the table and enjoy your rainbow!

You should have produced a beautifully layered rainbow in a jar with distinct lines that separate each layer of liquid without them mixing.

So what keeps all these layers all separated from each other? It’s how dense, or heavy, each liquid is. The corn syrup is heaviest, and sits nicely on the bottom. The dishwashing soap is not quite as heavy as the corn syrup, but it’s heavier than the olive oil, and so on.

Layering them from heaviest to lightest from the bottom up ensures that the rainbow maintains its distinct lines. 

What if you had added the layers in the reverse order? Would you still see a rainbow? Try it. What if you changed the colors around but added each liquid in the original order? Go for it. What happens if you mix your rainbow with a spoon? No matter which new experiments you attempt, be sure to record your results to learn even more about density.

Related learning resources

Add to collection, create new collection, new collection, new collection>, sign up to start collecting.

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

How To Make A Rainbow – Simple Science Experiments

Making a rainbow is a fun and educational science experiment that can be easily done at home or in the classroom.

It involves using a light source, such as sunlight or a flashlight, and a medium to separate the light into its component colors.

The result is a beautiful display of the colors of the rainbow, which can be used to teach about the nature of light and color.

This experiment is an engaging way to introduce children to the basics of optics and the physics of light.

How Are Rainbows Formed?

Sunlight or white light is a mixture of all the rainbow colors. The different rainbow colors are essentially mixed together to result in a white color.

You may wonder why when you mix all the different colors of paint together result in black instead of light. That is because light mixing is additive while pigment mixing is subtractive.

When light passes from one medium to another medium of a different density (e.g. from air to water ), the light bends. This is known as refraction of light ​1​  (More  light experiments ).

How much a light is refracted depends on the wavelength of the light. The shorter the wavelength, the more it bends. Because lights of different colors have different wavelengths , each color is refracted by different amounts.

Therefore, white light is split up after passing from air to water and the individual colors become visible. This dispersion of light allows us to see the spectrum of colors that form a rainbow ​2​ .

In nature, a rainbow is formed when sunlight is refracted on entering a droplet of water, reflected inside the back of the droplet and finally refracted again on leaving the droplet.

Seeing A Rainbow

To see a rainbow caused by sunlight, the sunlight needs to come from behind us because rainbows only appear in the part of the sky directly opposite the sun.

Red has the longest wavelength among the visible colors. So it tends to bend the least and the angle between the incident light and our line of sight for red is approximate 42 degrees. As a result, red appears on the top of the rainbow

Violet has the shortest wavelength. It tends to bend the most. To see violet, the angle between the incident light and our line of sight is roughly 40. So violet appears at the bottom of the rainbow.

Why Are Rainbows Arched?

Rainbows are not two dimensional . A rainbow is seen at an angle that is between 40-42 degrees from the incident sunlight . So all the water drops that produce each color in the rainbow lie on a three dimensional cone . Our eyes are at the tip of the cone.

That is why rainbows are arched. The circular shape below the ground is invisible.

Rainbow Experiment

Now are you ready to make some rainbows? Here are 3 easy ways to make your own rainbows at home. 

Warning: Adult supervision is vital in experiments involving sunlight. Do not look directly at the sun or at the reflection of sun in a mirror.

1. Rainbow Prism

One of the easiest and most visually stunning ways to see an artificial rainbow is by using a prism. Creating rainbows using a prism is really fun.

• strong sunlight
• glass prism
• white cardboard / paper (optional)
• adult supervision

Instructions

• Place a piece of white paper on the ground under the sunlight.
• Put the prism on or above the paper.

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2. Rainbow On The Wall

No prism? No problem. Using a small mirror and a glass, you can make a beautiful rainbow on the wall.

• a clear glass
• small mirror
• Fill the glass with water.

• Position the glass so that sunlight shines directly at the mirror. You may have to shift the mirror to find the right angle.
• Look for a reflection on the wall.  It would be easier to see if the room is dark.

3. Make A Rainbow Using Flashlight

You can still make a rainbow without natural light. Try this experiment using a whitelight flashlight.

• clear glass
• flashlight that emits strong focused white light . Flashlights that emit only yellowish light won’t work. Flashlights that don’t emit focused light also won’t work. Look for one with parabolic reflecting mirrors inside to focus the light, or one with a strong LED light.
• 2 pieces of white cardboard
• Cut a narrow rectangle in the middle of one piece of paper.

• Place the other piece of paper on the floor on the other side of the glass to catch the rainbow.

• Start from the glass and slowly move the flashlight farther and farther from the glass.

More Making a Rainbow Experiments

If you’re a rainbow enthusiast, want more rainbow experiments, or wonders what makes a rainbow, here are a few fun science projects for you.

• Rainbow Water
• Rainbow Walking Water
• Crystal Rainbow

Learn More About Rainbows

Have Fun With Rainbows

• 1. Jiang W, Chen RT, Lu X. Theory of light refraction at the surface of a photonic crystal. Phys Rev B . June 2005. doi: 10.1103/physrevb.71.245115
• 2. Whitaker RJ. Physics of the Rainbow. The Physics Teacher . May 1974:283-286. doi: 10.1119/1.2350374

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More From Forbes

Raising a glass to the growing market for non-alcoholic drinks.

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Savyll's non-alcoholic Bellini

Not so long ago, “fine dining” meant starting off your meal with a mixed drink before moving on to wine and possibly a postprandial digestif, but these days your “drink” might very well be a spirit-free cocktail, a non-alcoholic (NA) beer, or a de-alcoholized wine. According to IWSR Drinks Market Analysis , the NA category continues to grow, with the overall product volume increasing by 29% in one year. In 2023, millennials and Gen Z represented 62% of the market for these products.

For many, the trend is driven by concerns about mental and/or physical health, especially in light of recent reports undermining long-held beliefs about red wine’s heart benefits. But consumers are also seeking new flavors, pairings and even beverages with functional ingredients, such as medicinal plants and fungi, to counter specific symptoms—like Ryze ’s mushroom cocoa, which contains melatonin and reishi, and is billed as an aid for restful sleep.

With the expansion of this category, beverage manufacturers are getting creative about the drinks they produce and the way they market these brands. This was evident at last month’s Fancy Food Show in New York City, where even some booze-free teas and sodas were positioned as NA drinks—kind of like a vegan product touting its lack of cholesterol, something it never contained in the first place. Here are some of the most notable offerings at the show.

A Pre-Made Mocktail With Flavor And Texture

Savyll's NA versions of classic cocktails

For Avnish Babla, life in London’s corporate world meant frequent drinks with clients and colleagues, usually in environments where good NA options were slim. When his wife became pregnant with their first child, he decided to limit his consumption of alcohol as well. As someone who enjoyed entertaining and mixing cocktails for guests, Babla began crafting booze-free versions of his favorite drinks. In 2019, he left the corporate job and launched Savyll the following year. Currently, the brand features canned NA versions of the mojito, paloma, Bellini and Moscow mule, with additional varieties slated to debut later this year. While many mocktails have a thin texture, their flavor evaporating as soon as they hit your tongue, Savyll’s drinks benefit from a touch of vegetable glycerine (found in some wines and spirits), which gives them more weight and gets them closer to the mouthfeel of an alcoholic beverage. My favorite was the gingery Moscow mule (which won double gold in the 2023 San Francisco Ready-to-Drink Competition).

Curious About Non-Alcoholic Options

Nine curious flavor combinations from Curious Elixirs

One of the OG’s in the booze-free space is Curious Elixirs , founded by JW Wiseman in 2015. The company’s name actually predates the coining of the term “sober curious” to describe a movement that doesn’t necessarily call for total sobriety but rather a more mindful attitude toward the consumption of booze. While many NA drinks rely heavily on sweeteners to make up for the lack of alcohol, the team behind Curious Elixirs has created flavor combinations that contain only about 30 calories per serving and incorporate a variety of herbs and adaptogens. My favorite, Curious No. 4, is modeled on the Aperol spritz, offering a delightfully tart mix of blood orange, green mandarin, ginseng and turmeric, while No. 1 is modeled on the Negroni and includes rhodiola and gentian, which are said to boost energy. The newest member of the lineup—No. 9, a “sparkling rosé” made with chardonnay grape juice, echinacea and kanna—was launched this past May, just in time for summer gatherings.

Best High-Yield Savings Accounts Of 2024

Best 5% interest savings accounts of 2024, mixing delicious booze-free cocktails at home.

Bittermilk's NA Tom Collins–inspired bitters

The same company that created Barcoop Bevy (high-quality, large-format mixers for making bloody Marys, margaritas and the like) brings you Bittermilk , a line of NA mixers. Joe and MariElena Raya, the husband-and-wife team behind both brands, established their mixology bona fides at The Gin Joint, a Charleston-based craft cocktail bar they used to own. While bitters are typically made by soaking citrus peels, spices, barks, roots, berries and other natural ingredients in a neutral high-alcohol spirit, most cocktail recipes that call for them call suggest only a few drops, just enough to round out the flavor of the drink. But Bittermilk’s product line skips the alcohol entirely, bringing together the various flavor elements of a well-balanced cocktail, including acidity, sweetness and—naturally—bitterness. You can, of course, use these mixers in a boozy drink, but they’re also great blended generously with soda water. The combination of elderflower and hops works especially well in Bittermilk’s “Tom Collins.”

Chill Out With Adaptogenic Mushrooms

Adaptogenic aperitifs from Ceybon AF

In a playful take on a profane acronym, the abbreviation in Ceybon AF ’s name actually stands for “alcohol-free,” but its origin story has serious roots in the medical practice of Dr. Giulietta Octavio, a doctor of integrative Chinese medicine and clinical herbalism. At the height of the pandemic, Dr. Octavio’s patients admitted that they were drinking too much, as a way of coping with anxiety. With supply chain issues making it hard for her to get medicinal herbs and mushrooms from overseas, she began foraging these ingredients locally, in northern California, and creating concentrated “wellness elixirs.” When patients reported good results, she went on to develop a line of NA aperitifs featuring these adaptogens. Happy AF is inspired by mezcal’s smoky notes; Chill AF is her take on a Pimm’s cup; and Bright AF is a version of the Moscow mule. Produced in a Napa winery and packaged in elegant long-necked wine bottles, the beverages are sweetened with agave syrup, and each serving contains only 25 calories. A bottle of Chill AF—served chilled, of course—makes for a lovely post-meditation libation.

A Spirit-Free Shrub On A Medical Mission

Life Cider's line-up of cider vinegar beverages

The “life” in Life Cider ’s name reflects the experience of its creator. In 2014, after years of battling acid reflux and weight issues, Jon Pierre Francia came down with a reflux-inducted bout of pneumonia and nearly died. Once recovered, he began drinking apple cider vinegar in hopes of addressing the reflux but found the taste unpalatable, so he played around with different combinations and added raw honey, carbonated water and lemon juice. These experiments eventually led to Life Cider, a carbonated beverage that comes in flavors like black cherry, pineapple coconut and mango citrus. With only 30 calories per serving, each 12-ounce can contains one tablespoon of apple cider vinegar, along with the recommended daily allowance of vitamins C and D3, zinc and a super-dose of vitamin B12. Surprisingly, the taste is pleasant, particularly the berry pear flavor, whose tangy pop is well balanced by a delicate sweetness. Healing or not, I enjoyed it on the rocks in a lowball glass while pretending it was a NA shrub cocktail.

Bottoms up!

This is the third article in a series on this summer’s Fancy Food Show, held late last month in New York City. The other two pieces covered trends in the specialty food market and products made with sustainability in mind .

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