PURPOSE: To show that hot air is less dense than cold air by operating a hot air balloon.

DESCRIPTION: A 15-ampere hot air gun is used to inflate a hot air balloon. Within less than a couple of minutes the buoyant force becomes sufficient that the balloon will rise.

The sequence of photos below shows the balloon in various stages of inflation. Be careful not to let the hot air blast directly on the balloon plastic skin (upper left), or it will melt the plastic.

SUGGESTIONS:

REFERENCES: (PIRA unknown.)

EQUIPMENT: Mylar balloon, 15-amp heat gun.

SETUP TIME: None.