How Can You Explain Black Holes To A Kid?

This question originally appeared on Quora. Answer by Robert Frost.

1. Take a large piece of plastic food wrap (Saran Wrap) and hold it.
2. Put a small ball in the middle so that the sheet dips.
3. Pour a couple of drops of water on the sheet. They should roll down the wrap towards the ball. This illustrates gravity.
4. Remove the ball and have the child use his/her finger to push down and bend the sheet. They will see that the harder they push (heavier the object) the more the plastic wrap bends.
5. Have them push their finger hard enough to make a hole in the wrap. That would be an extremely heavy object.
6. Pour a couple of drops of water on the sheet. They should flow down and through the hole.
7. Explain that a black hole is an object so heavy that it bends space so much that anything that falls in can't ever come back (like the water that fell through the hole).