Eight Year Old Questions

Over the weekend my eight year son asked me two questions:

1. Why are clouds white?
2. Why is the moon cold?

Update: After thinking about question (2) a little bit, I was puzzled and so after the initial post I went back and asked him "But how do you know the moon is cold?" "Because it's cold at night." Oh, ok, I get it: The hot sun "comes out" during the day and warms up the earth and the "cold" moon "comes out" during the night and cools it down. Interesting.