Which is an example of convection? A. Hot air rises up a chimney, drawing cool room air into the fireplace.

B. You fry a hamburger in a pan.

C. You heat your cold hands as you stand near a campfire.

The hammering on a train track is often heard twice by workers farther down the track; first as the sound travels through the steel and second as the sound travels through the air. this suggests which graph is true?