Fun Science: Surprising saucers
Ages: 4 to 8.
Ingredients: Shallow dish, water, spices such as pepper or cinnamon, dish washing liquid.
Experiment: Fill a saucer with water. Add pepper, watch how it floats on the surface. Then, add one drop of dish soap, and watch the pepper run to all sides and the water spill over the edges.
What it teaches: How the soap disrupts the water's surface tension. "Most people think, 'Water is a liquid.' They don't think it's also sticky. Water molecules like to stick to one another and the shape creates surface tension."
A more psychedelic version: Add a few drops of food coloring to a saucer of milk. Dip a cotton swab in dishwashing liquid, then dip the swab in the center of the saucer and hold it steady. Watch as the soap turns the mixture into a kaleidoscope.