"warm Air Rises"

We are told that warm air rises. But you don't see air. Here is the way to show that warm air does, indeed, go upward.

MATERIALS: Meter stick (or any other stick), 2 paper bags (same size), paper clips, candle and matches

HOW TO DO IT: Exercise caution since this activity involves a flame. Suspend the stick at its center so that it is balanced and will tilt freely. Open the bags and tape one upside down at each end of the stick

Light the candle and hold it below the opening of one of the bags. In a minute or two, the air in that bag will heat and expand. Some of the air molecules will have to leave the bag, since the molecules in warm air have more energy and must occupy more space. Soon, the warm bag should lift up.

The rising of warm air and sinking of cold air is an important concept in weather. This is the cause of all wind movement in the earth.