Discovery at Home: Exploring Milk

What is in Milk?

Milk comes in many forms. It is available as a liquid or powder, and is sold in bottles, boxes, or cans. Milk may come from cow, grains, nuts or vegetables. Do you drink milk? What kind?

Milk contains different amounts of sugar, proteins, and fat (skim, 1%, 2%, whole, half-and-half, heavy cream….). Compare the ingredients of these 5 kinds of cow’s milk. What do you notice?

If you have milk in your house, what kinds do you have? How is it the same or different from these? Do you have milk that is not from a cow? Soymilk, rice milk, almond milk, coconut milk, pea milk, goat milk? (Tell us what you find at our Facebook page where we’ve posted a link to this activity: https://www.facebook.com/discoverycenter/) There are many reasons to choose what type of milk to drink. Why do you drink the milk you do?

Be a Scientist!

Scientists start by noticing things. What do you notice about what is in these different milks? What can you learn from the nutritional facts? Which ones have more fat? Less fat? Notice the serving sizes – are they all the same? If not, how do you compare one kind of milk to another? Taste, health, allergies, ethics – thinking about the many reasons people might choose a specific kind of milk.

Milk Fat Fun for Children & Adults

Here is a fun experiment to do with milk that will get you and your child(ren) exploring, and asking a lot of questions. Exploring, playing with the materials, and asking questions are what being curious is all about!

You will need milk, water, food coloring and dish soap. A cotton swab would be useful if available. (Hint: use milk with some fat content.)

1. Put some water in a rounded saucer and some milk in a second saucer.
2. Place 2-4 drops of food coloring in each. What do you notice?
3. Dip the cotton swab (or the tip of your finger) in dish soap and then gently touch the water in the center. What do you notice? Does anything happen? Then do the same with the milk. What do you notice?

4. Keep exploring. You might ask your child:

a. What are you noticing? How might you describe what you see? What could you try? How could you test that? What would happen if….?
b. When they describe what they want to do next, ask them first to predict – what do you think might happen if you add more soap? Try it!
c. The questions are endless. What do you think might happen if you add more soap? What will happen if it sits? What if it is mixed? How many times can you add soap and still get an explosion of color?
d. Hint for Adults: Don’t interrupt the exploration with information or expertise. Just keep asking questions.
e. Extend your experimentation by comparing the explosions of color using different kinds of milk or types of soap. The explorations are endless!

Background Information

While mostly water, milk also contains proteins and varying amounts of fats. If the milk you used had fat in it, you probably saw the food coloring stay as a drop until the soap was added (Step #2). And then – an explosion of color! The food coloring in just the water probably spread out some but did not change even when soap was added (Step #3). The addition of soap to the milk solution resulted in parts of the fat in the milk and parts of the soap particles (molecules) separating, interacting, combining, twisting, and moving. The more fat, the more movement. Once the pieces of soap and fat are all combined, the movement slows down. However, keep trying – sometimes more soap can lead to yet another explosion of color.

Want more information? Check out these sites:

https://www.stevespanglerscience.com/lab/experiments/milk-color-explosion/
https://www.acs.org/content/acs/en/education/whatischemistry/adventures-in-chemistry/experiments/colors-move.html