How long does it take for the Earth to Revolve around the Sun?

Bob notices that the shadow of the tree outside his house is changing through the day. Why?

Sun appears to rise in the__________and set in the ________.

How often do each of these phases of the moon appear?

At what time of the day will a shadow of a lamppost be the shortest?

The moon does not produce any light. Yet we can we see the moon in the sky. Why?

Which force keeps the planets orbiting the Sun?