Magic Milk Science Experiment

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The Magic Milk experiment is a quick and easy experiment that is sure to wow your preschooler.

The Magic Milk experiment shows how dish soap separates the fat and water molecules within milk using food coloring as the visual component. Milk is comprised of fats, water, and other substances. By adding dish soap, we affect the surface tension of the milk with “water-loving” and “water-hating” parts, which separates the fats and water. The food coloring shows this reaction!

This reaction could be more difficult to explain to a toddler, but I have some ideas for you below that could make it make sense.

The Magic Milk experiment is a quick and easy experiment to show the reaction of dish soap to milk
The Magic Milk science experiment

How to make the Magic Milk experiment

Supplies you will need

For the Magic Milk experiment, you’ll need:

  • A shallow bowl
  • 1 smaller bowl (for dish soap)
  • Food coloring
  • Whole milk (important!)
  • Q-tips
  • Dish soap

Before you start

It is important to use whole milk for this experiment because it has the highest fat. Since the Magic Milk experiment is all about how the dish soap separates water and fats in milk, you will want to use the highest fat milk possible.


Here is how to do the Magic Milk experiment with your toddler:

Step 1: Add whole milk to a shallow bowl

Add enough milk to cover bottom of bowl for Magic Milk experiment
Add milk to larger container

I used a pasta bowl for the milk, to give an idea of how shallow the bowl is here.

You do not have to add much; we added enough to cover the bottom of the bowl and that is plenty for the experiment.

Get your preschooler involved: if you are confident in their pouring skills, let them pour the milk into the bowl. Just know that it could get messy quickly!

Step 2: Add dish soap to a smaller bowl

Add a small amount of dish soap
Add dish soap to small container

A small amount of dish soap is enough here. We only need enough to dip a Q-Tip into the dish soap and saturate the cotton portion of the Q-Tip.

Step 3: Add food coloring to bowl with milk

Adding 1-2 drops of food coloring
Add your food coloring

Get creative! We added a drop or two in several spots around the bowl. See what fun color patterns you can make and how that affects the outcome. You can’t go wrong here.

Get your preschooler involved: I let my toddler add drops wherever she wanted around the bowl. I only had to ensure she knew how to get just one or two drops out the first couple of times and she was off!

Step 4: Dip Q-Tip in dish soap and touch colors to make the milk react

Using a Q-Tip soaked in dish soap to begin touching the colors in the milk for the Magic Milk experiment
Touching the colors with dish soap

Saturate your Q-Tip with the dish soap and simply touch the colors with your Q-Tip (no need to dunk your Q-Tip).

Get your preschooler involved: if you let your toddler do anything during this experiment, let them do this part! My toddler LOVED seeing the reaction as she touched each color.

Step 5: Experiment!

Experimenting with Magic Milk experiment by holding Q-Tip in milk
Experimenting with Magic Milk experiment by holding Q-Tip in milk

One fun experiment we did was to hold the Q-Tip in one spot on the milk for an extended period of time.

The result was SO COOL. You could see the colors flowing away from your Q-Tip, but it looked like they were even bubbling up from the bottom of the bowl to flow away.

Check out the entire video below to really see this part of the reaction.

The science behind the Magic Milk science experiment

The Magic Milk experiment is a fun and colorful experiment to learn about chemistry!

For the parent

Milk is made up of fat, protein, water, vitamins, and minerals.

Dish soap is a surfactant, which affects our milk’s surface tension with hydrophilic (attracted to water) and hydrophobic (repels water) portions.

When soap is added to the milk, the hydrophilic portion connects to the water molecules in the milk and the hydrophobic attaches to the fat molecules.

During this reaction, the food coloring is bumped around, causing the reaction you see in the experiment.

For the child

The milk you drink is made up of lots of things, including vitamins, water, and fat.

When we add dish soap to our milk with a Q-Tip, we are separating those fats and water inside the milk. It is happening at such a small level that there’s no way we could see it, so we have to add food coloring to show it happening.

Touching a Q-Tip with dish soap on it to the milk separates the fats and water really quickly, and we see that in how quickly the colors move away from our Q-Tip!

More chemistry experiments to try out with your child

FAQ about the Magic Milk Experiment

Why do I have to use whole milk in this experiment?

Whole milk has the highest fat content, and in turn gives the best reaction.

Here’s a great explanation of why a higher fat milk is better:

As the soap molecules race around to join up with the fat molecules, the fat molecules bend, roll, twist and contort in all directions. As the soap becomes evenly mixed with the milk, the action slows down and eventually stops. This is why milk with a higher fat content produces a better explosion of color: there’s just more fat to combine with all of those soap molecules.

Try adding another drop of soap to see if there’s any more movement. If so, you discovered there are still more fat molecules that haven’t found a partner in that big color dance. Add another drop of soap to start the process again.

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