A colorful surprise explosion when milk, food color, and dish soap collide! Who knew these three ingredients could make a burst of science magic when combined? It’s so addicting, your kids will want to do this one over and over.
What you need:
- Empty metal pie tin
- Whole milk
- Food Coloring (at least 2 different colors)
- Dish soap
- Eye dropper or q-tip
What you do:
- Fill the pie tin half way full of milk.
- Add several drops of different food coloring around the surface of the milk. Don’t mix.
- Take an eye dropper of dish soap or dish soap generously on the tip of the q-tip.
- Dot the milk surface with the soap.
- Watch what happens!
Why does it work?
Milk is mostly water but it also contains vitamins, minerals, proteins, and tiny droplets of fat suspended in solution. Fats and proteins are sensitive to changes in the surrounding solution (the milk).
When you add soap, the weak chemical bonds that hold the proteins in solution are altered. It’s a free for all! The molecules of protein and fat bend, roll, twist, and contort in all directions. The food color molecules are bumped and shoved everywhere, providing an easy way to observe all the invisible activity. At the same time, soap molecules combine to form a micelle, or cluster of soap molecules. These micelles distribute the fat in the milk.
This rapidly mixing fat and soap causes swirling and churning where a micelle meets a fat droplet. When there are micelles and fat droplets everywhere the motion stops.
There’s another reason the colors explode the way they do. Since milk is mostly water, it has surface tension like water. The drops of food coloring floating on the surface tend to stay put. Liquid soap wrecks the surface tension by breaking the cohesive bonds between water molecules and allowing the colors to zing throughout the milk.
Want more? Experiment and discover…
Try different color combinations.
Try using different types of milk (2%, 1% fat free). Does it change what’s happening?
Do different brands of dish soap make an impact?
So many ways to explore this one!