Genius by Stephen Hawking

How Many Stars Are There in the Galaxy?

Clip: Episode 2 | 1m 55s | Video has closed captioning.

The volunteers are given a spoon of sand with 50,000 grains. Each grain of sand represents a single star. They try to guess how many stars there are in the galaxy and then use the spoon of sand to create a pile of stars with their estimate. How big will the pile of sand be and how close will it be to the actual number of stars in our galaxy?