Milk and Dish Soap
- A shallow dish or tray (any size)
- Milk (fatty milk works best, whole milk and 1/2&1/2)
- Liquid dish soap
- Food Coloring
What To Do:
- Pour milk into tray approximately 1 cm deep (room temperature milk works best)
- Carefully place a few drops of food coloring (different colors) in the milk. Keep the colors seperated.
- Put 1-2 drops of dish soap into the center of the tray, NOT on the food coloring.
*The dish soap will cause the food coloring in the milk to tie-dye and mix the colors together*
*The toothpick can be used to gently touch the surface of the milk where the dish soap is, then use that toothpick to touch on of the food coloring spots, and watch what happens.*
Location and Appropriate Age:
- This demonstration does not make a mess and can be done outside or inside.
- This demonstration is great for all age groups.
How It Works:
- Food coloring is less dense than milk, so the drops of food coloring remain floating on the surface of the milk.
- The milk surrounding the drop of dish soap has higher surface tension and therefore pulls the dish soap away from the original point where it was added.
- The food coloring moves with the surface of the milk and so is pulled away from the dish soap. Inevitably the food coloring and dish soap touch, and when that happens the food coloring sinks. Eventually after this happens a few times the milk will essentially stir itself.