Series · 4 episodes · 6:58
Questions everyone asks
The simple questions children ask and adults rarely can answer.
Play from episode 1- 1
1:46Why is the sky blue?
Air knocks blue light aside about 6 times as often as red, so blue reaches you from all over the sky. At sunset the blue is gone before it arrives.
- 2
1:40Where rain comes from
A raindrop is about 100 times wider than a cloud droplet, so it holds a million times the water. Drops join as they fall until they are heavy enough to rain.
- 3
1:52Why the Moon has phases
The Sun always lights half the Moon; its phases are the angle we see that half from, not Earth's shadow. One lap takes 27.3 days, a cycle 29.5.
- 4
1:40Why do we sleep?
Sleep runs in cycles of about 90 minutes, with deep sleep early and REM later. Pressure from being awake and a 24-hour body clock set when you sleep.