What You’ll Need:
- Milk (whole or 2%)
- Bowl, dish
- Food coloring (3-4 different colors)
- Dishwashing soap (Dawn brand works well)
- Cotton swabs
What To Do:
- Pour milk into the bowl/dish – enough to completely cover the bottom to the depth of about 1/4″. Allow the milk to settle.
- Add one drop of each of the four colors of food coloring into the milk. Keep the drops close together in the center of the bowl.
- Find a new cotton swab for the next part of the experiment. Place a drop of liquid soap on the tip of the cotton swab.
- Place the soapy end of the cotton swab in the middle of the milk and hold it there for 10 to 15 seconds (not moving it or mixing it around.) Can you predict what may happen? Did anything happen?
- Now add another drop of soap to the tip of the cotton swab and try it again. Experiment with placing the cotton swab at different places in the milk. Notice that the colors in the milk continue to move even when the cotton swab is removed. What makes the food coloring in the milk move?