May 152019

Swirling Milk Science Experiment : In this post, we are going to discuss one of the easiest and my most preferred science experiment that you can try at home (just with products from your home). You know the best part – it just takes few minutes

Swirling Milk Science Experiment Go Science Girls

Science Concepts Discussed
Surface tension, properties of matter, Chemistry, Forces
Who is it for?

Both preschoolers and toddlers can do this. My younger one Tisha loved it to watch the fun. Even kindergarteners can work on this and ask them to guess color formation. You can explain color mixing with the primary and secondary color. But if you want to explain the advance science concepts behind it, that would be best for 5-6 year group or older kids.

What you need to do this Milk Swirl Experiment?

Things we need for swirling milk experiment

  1. Milk (whole milk or full fat milk preferred. You can do this with skim milk as well – just that the swirling motion will be less due to less fat content).
  2. Food colors (Blue, red, orange or any other color you may like. Choose at least two different contradicting colors).
  3. Dish Washing Liquid
  4. Plate or Bowl
  5. Pipette (optional)
  6. Pepper (optional)
  7. Pipe Cleaners (optional – you can also try out with cotton thread).

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Steps to Create Swirling Motion

1. Pour the milk from your container to the plate or bowl. Don’t waste too much of milk, just get it enough to dip your finger say up to 1 cm.

2. Add few drops of different food colors. We just added two or three drops of Blue, Red, Orange and Yellow food colors each. Too much of food colors will spoil the experiment. So add just few drops.
Food Colors added to milk - swirling milk experiment
3. Now add powdered pepper (this is an optional step). We wanted to make the motion more visible before adding too many colors to milk. Pepper powder would easily show the swirling motion in the milk. This step makes the milk solution ready for the experiment.

add powdered pepper to milk - create swirl

4. If you are fine to make your kid touch the dish washing liquid by hand, you can try it with bare hands. Otherwise use a paint brush or cotton buds.

Dip your hand (paint brush/cotton bud) in the dishwashing liquid and try to touch the milk surface lightly. Hurray! The pepper particles will move away from your hand. Then, try touching the place where you dropped food colors, it would create a swirling motion and you can see the colors flowing out of your hand. 

fingers near to milk solution - milk swirl experiment for kids
Pritika immersed the finger to create color motion 🙂

keep your finger in the swirling milk - science experiment for kids

The result was incredible to look and will amaze kids. My younger one started jumping on seeing these swirls while my elder one started screaming “What’s happening mom?”

4. Tisha (my younger one) was persistent in using her favorite “Bubble Wand” to drop the dish wash liquid, so I allowed her to try it with it. She started making her own version of Milk Swirl Experiment.
Getting swirling milk using bubble wands in dish soap

5. Finally, we wanted to try creating a color jet stream in milk. This was Pritika’s ( elder one) idea based on a youtube video. She immersed a piece of pipe cleaner (about half the size of the plate) in dish wash liquid and dropped the pipe cleaner in the milk. Surprisingly it created a stream of colors and looked like a small river of colors flowing from the pipe cleaner.

Making swirling milk using pipe cleaners in dish soap

Check glimpse of our whole Milk Swirl Experiment in the video below:

As a mom, I was more than happy that my kids enjoyed this science experiment at home. I allowed them to play with it too their heart’s content for about an hour. They in turn created milk swirls in so many different color combinations.

Now it is time to understand the science behind this activity.

Science behind Swirling Milk

Instead of just talking science basics, it would be better if you discuss the below questions with your kids.

Why did the dish soap make the milk swirl? Or what happens when you add soap to milk?

The dish soap liquid added to the milk with food colors, it reduces milk’s surface tension. Also the dish soap liquid attracts the fat particles in the milk to create a strong bond. Due to this strong bond creation, the food color and water in the milk gets pulled away from the fat particles. This results in colorful swirl motion in the experiment.  The swirl motion will occur whenever dish soap liquid is added to the milk but it won’t be evident and clearly visible unless we add food colors to the solution.

What effect does soap have on milk?

Milk cannot mix with Soap liquid; thus, the soap liquid when added to milk, just floats on top of milk. But in the meanwhile, the fat particles get attacked by soap and creates visible motion.

What is the purpose of the color changing milk experiment?

This experiment allows us to see the invisible activity that happens between soap and fat with the use of food colors.

Why is there movement of dye in the milk when soap is added?

Actually, the dye doesn’t create movement. When soap is added, the milk’s surface tension is reduced and the fat particles start moving to create a bond with soap liquid creating swirl motion. The dye thus shows the movement of fat in milk while soap tries to settle evenly on top of milk.

Why do milk and dish soap not mix? Or why does detergent react with milk?

As we know, milk is made mostly of water (and of course fat). Proteins and fats in milk are very susceptible to changes. So when the dish soap is added, the proteins and fats that were made by weak chemical bonds gets altered.  The fat and protein molecules starts to roll, bend and move in all directions resulting in swirl motion.

What is the science behind magic milk? Or what happens in the color changing milk experiment?

Change in surface tension of milk and chemical bond alteration of fats and proteins results in magic milk.

Is soap attracted to water, fat or both?

If you add soap to water, it would reduce the surface tension of water – resulting in weaker molecular stickiness. That is why it is used to clean clothes and dishes. However, fats on the other hand tries to create a strong bond with dish soap.

What other concepts can be discussed with kids?

For toddlers, it is the right time to introduce about how particles make up solids, liquids and gases.

swirling milk science activity for toddlers and preschoolers

Try this experiment and with water. Does soap gets mixed in water or creates a swirl?  
Let us know how did this science activity go with your kids?

Reference & Resources:

Color Changing Liquid – Lesson Plan from University of Nebraska
Milk Rainbow experiment – Detailed document by The Chemist
Get free Worksheet for Magic Milk Experiment from TeachersPayTeachers. We are making our own version of this worksheet with added features, we will make it available soon for our beloved readers. 

Caution…
The primary ingredient in this activity is milk and dish wash liquid ( a deadly combination). Dish wash liquid is NOT safe for consumption. There is high possibility for toddlers to be tempted to taste the milk mixed with dishwashing liquid. The attractive colors may add to the temptation. So we strongly advise you to be present with your kids all the time when your kid tries this experiment. Never to let your kids alone. Be with them and guide them all through the experiment. Decide if your kid can do it based on their health condition etc. Click and get more details.

Swirling Milk Experiment for kids by Go Science Girls

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