milk soap rainbow experiment

Cool Science Experiments Headquarters

Making Science Fun, Easy to Teach and Exciting to Learn!

Science Experiments

Magic Milk Science Experiment – Amazing Explosion of Color!

Did you know that it is easy to turn ordinary milk into a rainbow of crazy colors? With only four common kitchen items, kids are thrilled by the color explosion created by the hydrophilic and hydrophobic molecules in our magic ingredient!

Watch our demonstration video, then print out a materials list and instructions to plan for this simple and fun science experiment. Easy to understand explanation of how it works is included below.

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

Supplies Needed

• Milk (Must be either Whole or 2%)
• Food Coloring. The more colors the better
• Shallow Dish or Bowl

Magic Milk Science Lab Kit – Only $5

Use our easy Magic Milk 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!

Magic Milk Experiment Instructions

Step 1 – Pour some milk into a shallow dish or bowl until the milk covers the bottom.

Step 2 – Add some drops of food coloring on the milk. You can use a variety of colors, just be sure to add 3-4 drops of each color.

Step 3 – Add a drop of dish soap into the center of the milk.

Step 4 – Watch in amazement as the colors dances across the surface of the milk. Do you know what caused the colors to move around in the milk? Find out the answer in the how does this experiment work section below.

Video Tutorial

Detailed Magic Rainbow Milk Science Experiment Step by Step Instructions

How Does the Science Experiment Work

The key to the dancing colors in this experiment is soap! Soap molecules consist of a hydrophilic (“water-loving”) end and a hydrophobic (“water-fearing”) end. Water molecules are polar molecules that can dissolve other polar molecules. Fat (and oil) molecules are nonpolar molecules, so they cannot dissolve in water.

Milk is a mixture of water, fat, vitamins and minerals. When soap is added to the milk, it helps to separate the water and fat in the milk. When soap is mixed in with the fat and water, the hydrophobic end of the soap molecule breaks up the nonpolar fat molecules, and the hydrophilic end of the soap molecule links up with the polar water molecules. Now that the soap is connecting the fat and water, the nonpolar fat molecules can be carried by the polar water molecules.

As the soap molecules connect to the fat molecules, the molecules of the food coloring get pushed around everywhere resulting in an explosion of color! As the majority of soap molecules attach to the fat molecules and the soap spreads throughout the milk, the color explosion will slow and eventually stop. Add more soap and see if there are more fat molecules that haven’t attached to soap – if there are unattached fat molecules still, the color explosion will begin again.

This experiment works best with 2% and whole milk because they contain more fat.

Other Ideas to Try

Try this experiment again using milk with different fat percentages. Try it with skim milk, 1% milk, 2% milk, whole milk, half and half, and cream. Consider even trying evaporated milk and sweetened condensed milk. See how the amount of fat affects the explosion of color!

I hope you enjoyed the experiment as much as we did. Here are some printable instructions:

Magic Rainbow Milk Science Experiment

Instructions.

• Pour some milk into a shallow dish or bowl until the milk covers the bottom. Tip: Be sure to use either Whole or 2% Milk
• Add some drops of food coloring on the milk. You can use a variety of colors, just be sure to add 3-4 drops of each color.
• Add a drop of dish soap into the center of the milk
• Watch in amazement as the colors dances across the surface of the milk

Reader Interactions

November 11, 2019 at 6:47 pm

I did this in my science class and it worked really well! I looked at a lot of science experiments but couldn’t find one I liked and then I found this at the last minute and it was really good so thank you for sharing:)

April 12, 2023 at 9:03 pm

I agree, Emma. It has worked every time and was fun to watch! This explanation of the experiment is very informative. I have done this experiment a lot when I was younger. ☺️

August 19, 2020 at 11:48 am

It was pretty cool

October 19, 2021 at 8:33 pm

This was a really fun activity!

November 19, 2021 at 8:26 am

Because of this experiment I got to the finals of my Sci Expo

February 13, 2022 at 8:11 pm

It was actually pretty cool. I did this for my science project. Also, the colors came out really nice! i will definitely try again.

April 2, 2022 at 5:27 am

Thanks a million for these fantastic ideas and explanations!

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Save my name, email, and website in this browser for the next time I comment.

• Privacy Policy
• Disclosure Policy

Copyright © 2024 · Cool Science Experiments HQ

Get Your ALL ACCESS Shop Pass here →

Magic Milk Experiment

How do you make magic milk or color changing rainbow milk? Let us show you how easy and fun simple science experiments can be! The chemical reaction in this magic milk experiment is fun to watch and makes for great hands-on learning. The perfect kitchen science as you already have all the items for it in your kitchen!

Magic Milk Science Experiment

Watch the video:.

💡 Make this a science experiment or even a milk science fair project using the scientific method . Choose one variable to change and write a hypothesis to test. You could repeat the experiment with different types of milk, such as skim milk, and observe the changes.

Materials Needed:

• Full Fat Milk
• Liquid Food Coloring
• Dawn Dish Soap
• Cotton Swabs

NOTE: There are so many fat percentages available that the milk used is a fantastic variable to consider! Low-Fat Milk, Skim Milk, 1%, 2%, Half and Half, Cream, Heavy Whipping Cream…

Experiment Set Up:

STEP 1: Start pouring your whole milk into a shallow dish or flat bottom surface. You don’t need a lot of milk, just enough to cover the bottom and then some.

💡 If you have leftover milk, try our milk and vinegar plastic experim ent !

STEP 2: Next, you want to fill the top of the milk with drops of food coloring! Use as many different colors as you like.

💡 Use a variety of colors or give your magic milk experiment a theme for the season or holiday! See how to set up this experiment for St Patrick’s Day , Valentine’s Day, winter and even Christmas !

STEP 3: Pour a small amount of dish soap into a separate bowl, and touch your cotton swab tip to the dish soap to coat it. Bring it over to your milk dish and gently touch the surface of the milk with the soapy cotton swab!

💡 Try a cotton swab without dish soap first and see what happens. Talk about what is observed, then try the dish soap-soaked cotton swab and check out the difference. This is a great way to add more scientific thinking to the activity.

What happens? Make sure to read about how the magic milk experiment works below!

Remember, each time you try this magic milk experiment, it will look slightly different. It’s a fun fireworks science activity for the 4th of July or New Year!

Also, check out: Fireworks In A Jar Experiment

How Does The Magic Milk Experiment Work?

Milk is made up of minerals, proteins, and fats. Proteins and fats are susceptible to changes. When dish soap is added to the milk, the soap molecules run around and try to attach to the fat molecules in the milk.

This movement disrupts the surface tension of the milk and pushes the food coloring around. The food coloring looks like fireworks because it’s getting bumped around , causing a color explosion.

The soap breaks the surface tension of the milk. When the soap molecules head for the fats, they form spherical micelles. This causes movement and creates cool bursts and swirls of color. After all the fat molecules have been found and equilibrium has been reached, there is no more movement.

Are there any more fat molecules hiding? Try another cotton swab dipped in soap! 

💡 For younger students: Ask them to describe what they see as the colors spread, noting how adding soap causes movement in the milk. Focus on cause and effect – “What happens when we add soap?” and using descriptive language.

Click here to get your free printable science guide!

You’ll also be sent weekly projects to your inbox! We respect your privacy. Unsubscribe at any time.

Related Science Experiments

Here are some more fun experiments that explore surface tension and chemical reactions :

• Skittles Experiment: Arrange Skittles in a circle on a plate, add warm water, and watch the colors spread. The movement of color across the plate is similar to how soap moves food coloring in milk.
• Floating PaperClip: Carefully place a paperclip on the surface of a cup of water so it floats. Then add a drop of dish soap and observe how the paperclip sinks as the surface tension is broken.
• Pepper and Soap: Another way to show how soap breaks surface tension, similar to the Magic Milk experiment.
• Oil and Water: Use food coloring to observe how the oil and water don’t mix.
• Bubble Science: Use a bubble wand to blow bubbles and observe the colorful bubbles. This activity demonstrates how soap molecules stabilize bubbles by reducing surface tension.
• Drops on a Penny: Use a dropper to add drops of water to a penny until it overflows. Repeat with soapy water to see how soap affects surface tension.

Printable Science Projects Pack

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

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

17 Comments

This activity is a staple in my house! 🙂 I wanted to say that, even though you say it’s great for little kids, my older kids (6 and ELEVEN) still love this, too!!! I’m not kidding- my eleven year old son asked to do magic milk last month. 🙂 Great fun!

This looks like a terrific idea to do with my kindergarten class! However, is there a possible substitute I can use for the milk?

• Pingback: Erupting Lemon Volcano Chemistry for Kids Science Activities
• Pingback: 8 Homeschooling Tips for Busy Parents | The Mama Workshop

Interesting and funny experiments. I like fireworks activity. A ton of value in cheap science activities and experiments.

My son suggested swapping out the soap for sanitizer and it is awesome. The color just explodes!

• Pingback: Four July 4th Activities for Kids that Don't like Fireworks - Project Stella Resources
• Pingback: WowTurf | Milk Magic
• Pingback: 5 Toddler Friendly Science Experiments
• Pingback: Preschool Science Experiments and Science Activities
• Pingback: Valentines Day Science STEM Activities and Experiments
• Pingback: Ultimate survival guide for your child's spring break - The Novel Mama
• Pingback: Week 1 Activities – Mella Wines
• Pingback: At Home Activities for Kids – Devoted Homemaker

The experiment was fun. We read the explanation about the soap attaching to the fat molecules. We tried it with fat free milk and the same result occurred. Why?

I things with my 4 year old grandson, and this was amazing, we did over and over and when his mom came home from work, he had to show her. Thank you so much for sharing, as on a limited income your free things help me help him learn. Sincerely, it was fun looking forward to the next experiment.

Awesome! So glad to hear he loved it that much!

Comments are closed.

Subscribe to receive a free 5-Day STEM Challenge Guide

~ projects to try now ~.

GET OUR LATEST UPDATES!

Rainbow Milk Experiment

• Kindergartner
• Preschooler

Diving into the world of science doesn’t always require a lab coat and beakers; sometimes, all you need is a trip to the kitchen pantry. The Rainbow Milk Experiment is a perfect example of how everyday items can transform into an exciting and colorful learning experience. This activity not only captivates the visual senses but also introduces young minds to the intriguing concepts of chemistry and physics right from the comfort of home. Using milk, dish soap, and some creativity, children can witness a mesmerizing display of colors that swirl and mix as if by magic. But there’s science behind this magic, primarily the interaction between the fat molecules in the milk and the dish soap, creating a burst of kaleidoscopic movement that’s both educational and utterly fascinating.

Science Behind the Rainbow Milk Experiment

The science behind this experiment lies in the properties of milk, which contains fats and proteins, and the chemistry of dish soap, designed to break down grease. When dish soap is added to the milk, it races around to bond with the fat molecules, causing the swirling motion that moves the colors. This visual spectacle not only demonstrates the principles of chemical reactions but also provides a hands-on exploration of concepts like surface tension and the interaction between different substances. It’s a simple yet profound way to introduce children to the idea that even the milk on their breakfast table is full of scientific wonders.

Material List:

• Shallow dish
• Milk (whole milk works best for more dramatic effects)
• Cotton pads
• Washable markers in colors of the rainbow

Rainbow Milk Experiment Step-by-Step Instructions:

1. prepare the rainbow cotton pads:.

Begin by gathering your cotton pads and washable markers in a rainbow of colors. Lay out the cotton pads on a flat surface where you have enough room to get creative. Start by drawing rainbows across the pads, using the colors in the order you prefer. Feel free to get inventive with the patterns: try placing red in the center for some pads and on the edge for others to see how the position of colors might influence the swirling effect later on. For a twist, cut some of the cotton pads in half to form semi-circles or arches, and arrange the rainbow colors with red on the outer edge, mimicking a more traditional rainbow arch. This variation in designs will add an extra layer of excitement when you observe how differently each pad reacts in the milk.

2. Milk Setup:

Choose a shallow dish that’s broad enough to allow multiple cotton pads to float without crowding each other. Pour whole milk into the dish until the bottom is completely covered, but there’s no need for the milk to be more than a few millimeters deep. Whole milk is recommended because its higher fat content enhances the visual effect of the experiment. Make sure the milk is at room temperature to ensure the best reaction.

3. Dish Soap Magic:

Now for the secret ingredient that sets everything in motion: the dish soap. On each of your prepared rainbow cotton pads, gently place a few small drops of dish soap. Aim to distribute the drops evenly across the pads, but there’s no need to saturate them. The dish soap acts as a disruptor to the surface tension of the milk, which will cause the colors to spread and swirl when introduced to the liquid.

4. Launch the Experiment:

It’s time to start the experiment! Carefully pick up the cotton pads and lower them one by one into the dish of milk. If possible, try to add them to the milk at roughly the same time to simultaneously witness the reaction of multiple pads. This is where you’ll see the magic unfold as the dish soap on the cotton pads reacts with the milk. The colors will begin to move and swirl in beautiful, unpredictable patterns, creating a mesmerizing display of flowing rainbows. Each pad might behave slightly differently based on the arrangement of colors and the amount of soap, making for a unique spectacle every time.

How They Played:

My kids were eager to jump into this activity, each taking turns coloring the cotton pads with vibrant rainbows. The twins, both 4, were fascinated by how the colors started to spread and dance upon touching the milk, while my 7-year-old made predictions about how the patterns would change. They experimented with different placements and quantities of dish soap, observing how each variation affected the movement of colors. It turned into a delightful afternoon of hypothesis, observation, and lots of giggles.

Tips for Success:

• Use whole milk for more dramatic effects since its higher fat content creates more movement.
• Lay out a protective cover or do the experiment in an area that’s easy to clean, as things might get a little messy.
• Encourage kids to predict what will happen before dropping the cotton pads into the milk to foster critical thinking.

Skills Learned:

• Scientific Inquiry: Kids learn to ask questions, make predictions, and observe outcomes, fundamental skills in the scientific method.
• Understanding Chemical Reactions: This experiment provides a basic introduction to chemistry, demonstrating how substances interact in unexpected ways.
• Creativity: Drawing the rainbows allows children to express their creativity and see how art can blend with science.
• Patience and Observation: Watching the colors swirl and change teaches patience and attention to detail as kids take in the results of their experiment.

The Rainbow Milk Experiment is more than just a craft; it’s a doorway to discovery, offering a captivating blend of science, art, and hands-on fun. It’s a vivid reminder that sometimes, the most extraordinary lessons come from the simplest materials.

Play2Learn Toddler & Preschool Programs for Curious Toddlers

There is no limit to your toddler’s energy and curiosity. That energy and curiosity although a joy can be challenging at times. Their interest in just about everything around them is what makes them great learners. One and two year olds can soak up so much just from their senses!

But as a teacher or parent that thirst for learning can be exhausting. That is why I created this toddler and preschooler program. To help you get the most out of this time with your curious toddler without having to come up with creative ways to play and interact with them.

Play2Learn for Toddlers  includes 20 Units for toddlers. Each 2-week toddler unit has 20 super easy to set up and engaging activities for toddlers 18 months to 3 years.

Play2Learn Preschool  which includes 20 Units for preschoolers. Each 2-week preschoolers unit has 20 unique and easy to set up and engaging activities for preschoolers 3 years to 5 years.  That’s over 800 learning activities for your toddler and preschooler at your fingertips! So many ideas you and your child will never be bored again! 

These  toddler and preschool lesson plans and activities  will definitely keep you and your toddler and preschooler busy playing and learning!

Click here for more information: Play2Learn

Book:  Exciting Sensory Bins for Curious Kids

Did you know I wrote a book of sensory bins? Click here for more information  Exciting Sensory Bin for Curious Kids . Or grab your copy at  Amazon . 

Boring afternoons are made exciting with awesome animal-based bins, like Salty Shark Bay or Yarn Farm. Pretend play bins like Birthday Cake Sensory Play or Bubble Tea Party encourage creativity and imagination. And your kids will have so much fun they won’t even know they’re getting smarter with STEAM (science, technology, engineering, art and math) activities like Sink or Float Soup, Magnetic Letter Hunt or Ice Cream Scoop and Count.

Designed for toddlers 18 months and up.

Book:  Super STEAM Activity Book for Kids

Learning all about science, technology, engineering, art, and math sets kids up for scholastic success―and it can be so much fun! Watch kids enjoy building STEAM skills as they color friendly fish, help water find its way to tree roots, solve math problems with mazes, and more. 

Find out more and grab your copy  here .

Designed for preschoolers 3 years old and up.

Book:  Big Book of Riddles for Kids

Riddle me this: What’s an exciting way to practice critical thinking while having a blast?  The Big Riddle Book for Kids , of course! From hilarious puns to tough brain teasers, kids can build problem-solving skills with hundreds of riddles tha. t show them how to think outside the box.

• 350 riddles for kids —Have hours of fun with riddles, puns and jokes, and math and logic puzzles that’ll get their wheels turning!
• Level up their skills —Riddles get trickier as kids progress through the book, challenging them as they get better at solving puzzles!
• Double-check their work —Kids can check their answers in the back of the book with a handy answer key.

Help children expand their minds while having fun with this puzzle book for kids!

Designed for kids ages 6 years   old and up.

TV Show:  Curious Crafting

I’m so excited to share my crafting TV show  Curious Crafting  which launched in July 2022 on  TVOkids  and  TVOkids YouTube ! Season 2 aired in August 2023! My show was also nominated in 2023 for Best Live Action Preschool Series by the Youth Media Alliance Awards of Excellence.

Curious Crafting Season 1 is also now airing in Australia on ABC ! Watch it here !

Set in the ultimate crafting space, Curious Crafting is a short form pre-school age series about the joy of making crafts. I lead a rotating cast of adorable little preschoolers (including my own) making magic out of common household objects.

In each episode we transform recycled items into magical crafts like a milk carton school bus, paper bag puppet or cotton pad turtle. The crafters learn and laugh their way through each activity while demonstrating what their young imaginations can create. 

Curious Crafting shares the adventure and joy of making art with takeaway lessons for creating crafts at home.

This show designed for toddlers and preschoolers 2.5 years old and up. 

Instructions  

• Prepare the Rainbow Cotton Pads:  Use the markers to draw rainbows on the cotton pads. Experiment with different designs – some with red starting in the middle, others with red on the outside. For variety, cut the cotton pads in half and create arches with the colors in different orders.
• Milk Setup:  Fill a shallow dish with milk. The milk should cover the bottom completely but doesn't need to be too deep.
• Dish Soap Magic:  Place a few small drops of dish soap on the decorated cotton pads. This will be the catalyst for the magic to happen.
• Launch the Experiment:  Carefully drop the cotton pads into the milk. Try to add them around the same time to watch the colors move, swirl, and create a stunning display.

Did You Try This Idea?

Filed Under:

• St. Patrick's Day

Other Posts You May Like...

Free Printable 2025 New Year's Eve Party Hat

Cork Painted Ornament Christmas Card

Folded Paper Christmas Tree Card

Bow Tie Pasta Wreath Christmas Card Craft

Review and rate this post cancel reply.

I love hearing from you! Submit your question or review here. Your email address will not be published. Required fields are marked*.

This site uses Akismet to reduce spam. Learn how your comment data is processed .

Rainbow Magic Milk Science Experiment

Science or magic? This rainbow dancing Magic Milk Science Experiment is a fun way to explore the chemistry of surface tension.

This is one very cool experiment. To kids, it can appear more than a little magical but the effect is all science – no magic here. It’s a chemical reaction with surface tension in action! Check the explanation below the experiment procedure for more information about how and why the magic milk experiment works.

You will need:

• 1 Tablespoon dish soap/dishwashing liquid in a small container
• 1 1/2 cups of whole/full fat milk
• 10 drops of each of your chosen colours of liquid food colouring
• Dinner plate
• Cotton swab

1. Pour about one tablespoon of dish soap into a small container. Set aside.

2. Carefully pour milk onto a dinner plate. It’s okay if you see bubbles in the milk. Let the milk sit for a minute so that it stops moving in the dish, becoming completely still.

3. Drop food colouring into the milk in the middle of the dish. Keep the colours separate. The food colouring may spread out slightly as you can see pictured in our photos. You can get creative with where you place the drops and space them out how you wish.

We used neon food colouring for this activity, which looks really cool but you can stick with a classic colour palette or experiment with using just warm colours or cool colours.

4. Dip a cotton swab into the dish soap.

5. Place the dipped cotton swab in the middle of a colour and observe the magical reaction! You should see the colours start to spread out towards the sides of the plate. They will continue to move and change over time.

You can repeat this step a few times, placing the cotton swab in different areas of the milk/colouring mix.

Tip: Kids can also take their dipped cotton swab and “draw” or “swirl” in the food colouring. Eventually the colours will mix together until the milk becomes one color.

If you allow the milk to sit a while before all colours are mixed completely together, you will see the milk continue to move and change in really neat ways, as you can see in the photos.

Watch over time how different things look!

6. When complete, dispose of milk in the sink.

The Science Behind the Magic Milk Experiment:

Milk as a liquid is composed primarily of water, with much smaller percentages of carbohydrate, fat, protein and vitamins/minerals. Milk composition does vary according to the species and breed of animal, the animal’s feed and the stage of lactation of the cow.

Because of its web of hydrogen bonds, water molecules are highly attracted to each other, resulting in a high surface tension.

When the dish soap is added to the milk the soap acts as a surfactant , reducing the surface tension of the milk so that the food colouring can spread out.

Surfactant (definition): substance such as a detergent that, when added to a liquid, reduces its surface tension, thereby increasing its spreading and wetting properties. (source: britannica.com)

At the same time, the phosphates in the dish soap are reacting with the fat and protein content of the milk – the soap is trying to grab the globules of fat out of the milk to break them down, just like dish soap breaks down the grease when washing up. This interaction causes the fat particles to move around, creating the resulting swirls of moving colour.

For more STEM fun involving magic and colour, be sure to check out our cool eResource – Rainbows & Kaleidoscopes: 25 STEAM Activities Exploring Colour (and Color!) .

For fun, watch the magic milk experiment in action on a HUGE scale;

Christie Burnett is a teacher, author and mother of two. She created Childhood 101 as a place for teachers and parents to find engaging, high quality learning ideas.

Color Explosion Magic Milk Experiment and Science Fair Project

Want an extremely fun, easy, inexpensive experiment with serious WOW factor? You’ve got it with this Color Explosion Magic Milk Experiment that let’s kids explore a fireworks explosion of rainbow colours that appear to move and change like magic! It’s not magic though, it’s science. This easy science experiment is a must do for all ages. Today we have taken things even deeper by developing an entire Science Fair Project around Magic Milk.

Magic Milk Science Experiment

Table of Contents

Disclaimer: This article may contain commission or affiliate links. As an Amazon Influencer I earn from qualifying purchases. Not seeing our videos? Turn off any adblockers to ensure our video feed can be seen. Or visit our YouTube channel to see if the video has been uploaded there. We are slowly uploading our archives. Thanks!

With all the crazy experiments we have done around here, from launching baking soda and vinegar rockets, to building light up circuit bugs, to magic colour changing oobleck, sometimes it’s the simple experiments that surprise us the most! This Magic Milk experiment did exactly that.

With a very simple set up, and items from the kitchen, we ended up spending an entire afternoon experimenting, testing and learning. All with lots of mesmerized faces, quietly watching in awe what was happening in front of them.

Here’s the thing with Magic Milk experiments, they are extremely calming and relaxing to watch. It’s like a scientific calm down dish, instead of a calm down bottle. If you need an activity to keep the kids calmly entertained as they learn, this is it!

EASY SCIENCE EXPERIMENT – MAGIC MILK

The quick and easy way to do Magic Milk is to take your milk, whatever you have in your fridge should work (as we proved with our science fair project below), then you just need a pie plate or shallow dish, dish soap and food coloring.

Fill the dish with milk

Pour milk into the dish, we made ours about 2cm deep. We used a variety of milks in our science fair project below. You should be able to use whatever you have in the fridge. Let it settle for a moment, this will take more time the higher the fat content.

Add drops of food coloring

Scatter some drops of food coloring in the milk.

Add dish soap

Use a Q-tip or pipette to add a drop of dish soap to the center of the plate and watch what happens!

MAGIC MILK SCIENCE FAIR PROJECT

The joy of having kids that have been raised to be creative, imaginative thinkers, who embrace the Scientific Method, is that they have so many amazing questions. Very quickly our Magic Milk Experiment became a Magic Milk Science Fair Project.

HOW DOES THE FAT CONTENT OF THE MILK AFFECT THE MAGIC MILK EXPERIMENT RESULTS?

That was the big question for our science fair project. We wanted to know if the fireworks of colors created by the dish soap in milk would change at all based on the type of milk or cream we used. Specifically we look at fat content.

RESEARCH INTO MAGIC MILK

Our research actually led us to some conflicting and confusing information about what exactly was happening during the Magic Milk experiment. Finally we found some concrete answers that made sense, especially once we did our experiments. Turns out the whole things is based on surface tension and the polarity of molecules. More on the science in a moment!

Resources on Magic Milk include Scientific American and American Chemical Society .

HYPOTHESIS: Higher Fat Content EQUALS SLOWER COLOR MOVEMENT

After doing our research, I pulled out the milks we had available. We were going to test 2% fat (milk), 18% fat (coffee cream) and 33% fat (whipping cream). I asked the kids to come up with their predictions and best educated guesses for what might happen. Their hypothesis was that the higher the milk fat content, the slower the colors would move through the milk.

HOW TO DO THE MAGIC MILK EXPERIMENT

Next we set up our experiments. Our constant variables were our Dawn dish soap applied in the middle of the plate with a Q-tip, milk 2 cm deep in a pie dish so the amount of milk was consistent, a consistent number of food coloring drops scattered in a similar pattern each time.

Our independent variable, the one thing we changed each time, was the fat content of our milk. We used 2%, 18% and 33%.

For our dependent variable we studied how the colors exploded and moved after the dish soap was added. We watched for changes in how fast colors exploded across the milk and if there were different patterns in how the colors moved. We also timed how long the colors continued to move.

Check out our Magic Milk Color Explosion Video!

Results of magic milk science fair experiment.

Our results were striking! The 2% milk rapidly exploded with colors that flew around the plate. In a short amount of time the colors started blending together and the dish soap, which stays as a little bubble, started floating around pushing reactions around the plate. The colors moved and blended about, constantly moving and changing. There was a lot of action with the rainbow of colors.

The 18% moved more slowly, the colors tended to stay together for a very long time without mixing. It also took a lot longer for the dish soap bubble to start moving around the plate.

Once it did start moving, slowly, it did start forcing more mixing of the colors. We found the colors pushed to the edges of the plate in a multi-colored ring.

This color blocking is very similar to what we saw in the Skittles Science Experiment . This made us wonder about the possibility of water stratification and concentration gradient playing a role in our results as well.

33% gave us the most astonishing and amazing results. The colors spread in fractals. Branching out in short little bursts. Like leafless branches, that never mixed into the milk. The soap bubble did not move, staying anchored in the middle of the plate where we had placed it. Very minimal mixing of the colors occurred, only happening when two fractals accidentally crossed paths.

With all three we stopped our stop watch at 15 minutes as the reactions and movement were still ongoing and, although they had slowed, they didn’t seem to be ending any time soon.

I mentioned earlier that when we were doing our research we came across from conflicting and even confusing information on the possible science behind magic milk. Our experiment allowed us to study how the fat content affected the movement of colours, allowing us to draw solid conclusions, informed by our research, into what exactly is happening.

Our hypothesis was correct, but our results lead to even more fascinating findings!

Conclusion – The Science Behind Magic Milk and Fat Content

With our Magic Milk Science Fair Project we were able to study the effect fat content had on the movement of colour when dish soap is added. Our results tell us that fat content plays a large role, but the reason may be surprising.

Liquids have something called surface tension. Water, milk, and cream are made up of molecules that have positive and negative charges on their surface. Just like magnets these charges allow them to attract and repel other molecules. When milk or cream is by itself, it’s molecules are surrounded by the same type of molecules, creating a nicely balanced push and pull. The exception is the top which is exposed to air which pushes down on the liquid, creating surface tension on the top of the liquid.

There is a substance that affects a liquid’s surface tension, it’s called a surfactant. Dish soap is mostly comprised of surfactants. It has a hydrophilic part that is attracted to the water and a hydrophobic part that wants to interact with the fat molecules and repels water.

It’s all about surface tension

The pushing and pulling of the fat and water molecules in the milk separates them, resulting in a decrease of the surface tension.

We see a big difference between our various fat content milks due to the different ratios of fat to water in the liquids. The higher fat content milk is much thicker. We can see this before adding the dish soap if we just look at the food colouring drops. The food colouring spreads significantly in 2%, spreads a little in 18% and doesn’t move at all in 33%.

This means, in our 33% milk, there is less water for the hydrophilic part to attract, and way too much fat for the hydrophobic part to ineract with. The surfactant (dish soap), has very limited effect on the surface tension, which remains quite a viscous, stable liquid. This leads to the fractal style, very limited spread of colour we see in the high fat milk.

In the 2% milk we have lots of water and some fat, allowing the surface tension to be affected easily. This results in a dramatic dance of color.

FURTHER STUDIES IN MAGIC MILK

Already the kids have identified more testing we can do in the future. This includes testing different surfactants. They wonder how shampoo or soaps may affect our results. They also wondered if there would be a difference if we used a oil or gel color instead of liquid food coloring (which is mostly water).

The kids also want to test lower percentage milks like skim and 1%, plus other types of milk like soy, coconut, goat milk, etc. to see how the different types of milk react.

MORE SCIENCE FAIR PROJECT IDEAS

Magic Milk Experiment

Explore the magical and explosive colourful experiment that involves a reaction between milk and dish soap.

• 1/2 – 1 cup milk experiment with different percentage fat milks and creams to see how it affects the results
• 1 tsp dish soap
• bottles food colouring in a variety of colours

Instructions

Pour milk into the shallow dish until it is about 1 to 2 cm deep. The amount of milk required will vary based on the size of your dish.

Add drops of food colouring to the milk.

Take the Q-Tip and dip it into the dish soap, then place the q-tip into the middle of the prepared milk and watch the reaction. You can remove the q-tip after a few seconds and the reaction will continue. The pattern of the reaction and duration will vary based on the fat content of your milk or cream. Experiment with a variety to see how your results change.

5 Days of Smart STEM Ideas for Kids

Get started in STEM with easy, engaging activities.

Magic Rainbow Milk

Bring a little color and magic with this super simple and fascinating science experiment for kids. Like our rainbow jar , rainbow milk is a simple science activity with a big “WOW!” factor.

Follow the simple step-by-step below and then grab 30 more easy-to-follow science experiments kids will beg to repeat (plus a no prep science journal to keep track of their results!) in our shop !

Getting Ready

To make rainbow milk , you can choose to keep it super simple and use only one kind of milk, or you can really get those scientific wheels turning and compare what happens with various kinds of milk.  Whatever you choose, the set up only takes a few minutes.

To prep, I gathered a few supplies:

• A pint of 2% or whole milk
• A pint of fat free and heavy cream (if you choose to compare milks)
• A shallow pan or plate for each type of milk
• Non-gel food coloring
• A measuring cup

Making Rainbow Milk

As soon as I walked outside with the armful of supplies, my 4 year-old came running over.  I lined up the three pie pans and placed a carton of milk in front of each pan.  Then, I asked her to measure two cups of fat free milk for the first pan.  She carefully measured, poured and then repeated with the whole milk and heavy cream.

Starting with the center pan of whole milk, I placed two drops of each color (red, yellow, green, blue) in the center of the pan.  I handed her a clean Q-tip and asked her, “What do you predict will happen if you place the Q-tip in the center of the milk but don’t mix it?”

“It will all mix together,” she quickly replied.

“Let’s see if your prediction is right,” I said as I helped her insert the Q-tip into the milk without mixing.

“It didn’t do anything,” A said with disappointment.

Next, I added a drop of dish soap to a new Q-tip and asked A what she thought would happen if she placed the Q-tip with soap into the milk.  “Nothing,” she answered.  A was fascinated when she carefully put the Q-tip into the milk and the colors instantly swirled around.  Rainbow milk!  She kept placing the Q-tip in and out of the milk to watch the colors race into a swirly rainbow.

“What do you think happened to the rainbow milk?” I asked A.

“The soap made the colors move,” A answered.  I explained how milk is made up of many things including water and fats and that fats act like oil.  We have done experiments with oil and water before so she knows water and oil don’t like each other.  I then explained how one side of soap like oil/fat and one side likes water, so when the soap was added to the milk, the soap molecules moved through the milk, looking for fat.

“The soap moving through the milk made the colors move,” I said to A.  “Now if we did this with milk that had no fat, what do you predict will happen?” I asked.

“I don’t know,” she replied.

“If there is no fat to search for, do you think the soap will move?” I asked.

“No,” A said.  So, we repeated adding the dye to the fat free milk to attempt rainbow milk again.  This time when I handed her the clean Q-tip I asked her why we are trying it with a clean Q-tip.  I explained we had to see if a plain Q-tip would cause a reaction.  Since we know it didn’t do anything, we know that it was the soap that was causing the colors to move.  “The plain Q-tip is what scientists call the control, ” I told A.  We repeated the experiment with a soapy Q-tip and was surprised when the dye actually moved.

“Hey, it moved!” A exclaimed.  Turns out fat free milk isn’t truly fat free.

“Does that one have fat in it?” she asked pointing to the heavy cream.  “Yes, it has a lot of fat,” I replied.  We predicted the dye would move a lot.  Again, we were surprised when the dye didn’t move at all.  “What do you think happened?” I asked.  “Did you notice something about the cream when you poured it?” I questioned.

“It was thick,” A said as she stuck her finger in.  “Do you think the thickness made it hard for the soap to move?”  She leaned over the pan to look closer and noticed the soap was still sitting in a little drop in the cream.

“The soap is right there, it didn’t move at all,” she said.  Then, she quickly moved back to the first pan to dip her Q-tip back in.

We ended up pouring out the pans and repeating the experiment with the whole milk for A and her little brother to make the magic rainbows swirl.  This experiment was a hit and a easy way to introduce some science terms like prediction, control, reaction, and result.  We’ll be repeating it again and again as it was simply magical!

Get 30 More Science Experiments!

Grab 30 easy-to-follow science experiments kids will beg to repeat (plus a no prep science journal to keep track of their results!) in our shop !

Similar Posts

Exploding Pop Rockets

Magic Balloons

Growing Germs: Kids’ Science Experiment

My Little Sprout House

Magic Pipe Cleaners

Rainbow Jar

11 comments.

Very interesting really great

I have grandchildren ages 4 to 12 that will enjoy doing this with us.

Awesome projects!

Thanks, Jess! Enjoy!

As a grandmother ILove it.

We’re so glad you’re enjoying it! I’m sure your grandkids love getting to do things like this with you 😀 Warmly, Ashley // Happiness Ambassador

Thank You for the Info. I am going to do this project for our science fair.

Wonderful! I hope it turns out amazing! Warmly, Ashley // Happiness Ambassador

• Pingback: Rainbow Science Experiments for Bright, Happy Learning
• Pingback: Dad Likes Sports, But What Do the Kids Like? | Diaper Dads

This is so fun. All 3 children loved it. One observation I would like to make is we tried it with plain water (no fat, needless to say). Did the color move? Well, you try and see. My conclusion is fat is not the factor (or at least not the only factor).

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *