A shallow bowl or pie dish
Milk (Optional: Use 1% and half and half to compare results, but you can use what you have)
A couple drops of liquid dish soap
A cotton swab
- Pour enough milk into the shallow bowl or pie dish
- Add a couple drops of each color of the food coloring
- Dip the swab into the liquid dish soap
- Dip that swab into the milk and watch the explosion of colors
When liquid dish soap is added to milk with drops of food coloring on the surface, the soap reduces the surface tension of the milk and reacts with the fat. This interaction causes the fat particles in the milk to move and create swirls of color.
Try picking up the dish and putting it back down again to observe what happens. Try dipping the cotton swab right into the center of one of the color droplets, or dip the swab into the white spots between the color drops. When the action slows down, dip the other end of the cotton swab into the dish soap and start experimenting again!