Kindergarten science lab classes begin the year with a set of lessons exploring the five senses. This week we kick things off with one of my personal favorites – Exploding Colors! Simple, beautiful, a perfect challenge for this age group. Also good for kids of any age.
Not all animals see color the same way. Humans are among the few animals who see all the colors of the rainbow. This activity let’s one see how mixing any two of the primary colors really does produce the three secondary colors. First, you need a shallow bowl. Pour about 2 cm of milk into the bowl. Put one drop of red, one drop of blue, and one drop of yellow food coloring into the milk. Try to arrange them near the middle of the bowl, in a triangle shape. It can be a bit of a challenge for a kindergartner to get just one drop. Let them do it. When an adult helps too much, it takes away from a youngsters sense of accomplishment. If they get more than one drop, it’s ok. If you have trouble trying to help too much, get your own bowl!
Put 1/4 of a teaspoon of dish detergent in a bottle cap or a spoon. Find a toothpick. Dip the toothpick in the dish soap. Just a tiny bit is enough – much less than a whole drop. Touch the toothpick to the surface of the milk. Don’t push it down into the milk, just touch the surface. Try touching one of the spots of color. Touch again somewhere else. And again, a third place. What happens each time you touch the soapy toothpick to the milk? Try getting a little more soap on your toothpick and touching all around. Later, you can stir a little bit, gently. What happens then?
Here are a few questions to keep you thinking…
What happens where two of the food colors mix together? What kind of milk works best: skim, 2%, or whole milk? Does it matter how deep the milk is? Does the type of soap make any difference?
And, what is surface tension?
Here’s a pdf you may print, if you wish: Exploding Colors