The water will swell up above the bowl, but will not spill over. Ask campers how a bowl full of water could hold marbles. The answer is that water has a characteristic called cohesion or we say that water has a skin. Molecule Movement You will need a pie pan, a variety of colors of food coloring, milk, and liquid dishwashing detergent. Ask campers what they think will happen to food coloring floating on milk when detergent is added.
Directions Fill the pie pan about half full of milk.
Drop one drop of dish detergent along the inside of the pie pan and observe what happens. Empty the pan and repeat the activity. Observations Generally, water molecules stick together, which is why the food coloring floats on top of the milk. The detergent causes the water molecules to separate, breaking the food coloring into tiny droplets. This is what happens when you wash clothes or take a bath.