What happens to the air inside a hot air balloon when it is heated?

When the air inside a hot air balloon is heated, the following steps occur:

1. The burner, located at the mouth of the balloon, is ignited to produce a flame which heats the air inside the balloon.

2. As the air inside the balloon gets heated, it becomes less dense than the cooler air outside the balloon. This is because the molecules of hot air move faster and spread out, reducing the air's density.

3. The difference in temperature creates a buoyant force. Buoyancy is the principle that explains why objects float in water or air. In this case, the hot air balloon floats because the hot air inside the balloon is less dense than the cooler air outside.

4. As long as the air inside the balloon is kept hotter than the air outside, the balloon will continue to rise. If the air inside cools down or the air outside warms up, the balloon will begin to descend.

5. To maintain the balloon's altitude or to ascend further, more heat is applied to the air inside the balloon. To descend, the pilot can either stop heating the air inside or release some of the hot air through a vent at the top of the balloon.