My name's Earl, and I'm a roving web wanderer. Every weekday, I answer a question from curious folks like you. Laine, Age 10 Dear Laine, I floated over to the Hot Air Ballooning category and found Facts about Ballooning on the Britannic Challenge web site.
Warm air rises.
If warm air is contained in a lightweight bag it will rise until the temperature of the air inside the bag matches the air outside. As the air cools, the bag starts to descend. The NOVA Balloon Race site has great pictures of the first balloons from the late 18th century. They are equipped with an instrument panel with a compass, altimeter, fuel gauge, and more. This makes modern balloon rides safe and comfortable, although the burner does get warm and rather loud at times.