F2-12
Show that hot air is less dense than cold air by operating a hot air balloon.
A 15-ampere hot air gun is used to inflate a hot air balloon. As the air inside is heated, its density decreases with respect to the cooler outside atmosphere. Within less than a couple of minutes, the buoyant force becomes sufficient that the balloon will rise.

Invite students to predict what will happen as the air cools.
OS4

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