Send it to the corner
This simply illustrates the same principle as the one behind the
previous activity (soap-powered boat).
- Fill a round bowl (like a cereal bowl) with water.
- Spread black pepper on top of the water. It is preferable for the
pepper to be finely ground, so that it is light. If the pepper you
have is coarsely ground then you can use talcum powder
instead.
- Ask your child to dip their finger in the middle of the
bowl. Ask them to repeat it after they spread a drop of soap on the
finger.
Explanation:
The soap reduces the surface tension and this causes the pepper to be
pulled away from the middle.
The two pictures show how the pepper essentially stays in place when a
q-tip without soap is used whereas within a fraction of a second, the
pepper moves away from the q-tip when it has been dipped in soap.
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