Problem 1: You go outside on a hot, sunny summer day and you feel the warm sun on your skin. What causes this warmth?

AThe sun heats the air directly around your skin.

BWaves of light carry energy directly to your skin.

CLight causes surface waves on your skin.

DWater vapor in the air warms your skin.

PRoblem 2: When a water wave runs into you at the beach, what causes you to get knocked down?

Aair molecules in front of the wave

Bthe wave's energy

Cperiodic motion

Dfriction