EXPLOSION OF COLOR
Two medium sized plates
Milk, Cream, or Elmer’s Glue
1. Pour the milk, cream, or Elmer’s glue into your first plate. Make sure to pour enough that the bottom is completely covered. Allow the liquid to settle.
2. Add drops of food coloring to the liquid. You can have fun with it but don’t add too much or you won’t be able to see the movement.
3. Use a Q-tip and dip it into the soap that you have ready on your second place.
4. Carefully put the Q-tip with soap on the end into the center of the mixture. Record what happens.
What do you notice about the movement? Does it continue if you lift the Q-tip out of the mixture? What role does the soap play? Experiment using different kinds of milk or even cream. Is the movement faster or slower? Why do you think this is?
HINT: Why do you think soap is needed if you are washing the glue off of your hands?
ANSWER: In the milk, cream, and even glue is fat. Fat is made of several molecules which are non-polar, or “hydrophobic”. This means they don’t dissolve in water. Soap, however, is made up of non-polar and polar molecules. Meaning that it bonds with soap but it will also bond with non-polar molecules like fat. When you add the soap to the mixture you are seeing the movement of those soap molecules as they spread throughout the liquid, bonding with the fat molecules. Try adding another drop of soap to your mixture, is there more movement? Why do you think there is or is not more movement?
Check out our YouTube channel to watch a video of this experiment!