Why would heating the gas in an air balloon make the balloon rise?
The correct answer and explanation is :
Heating the gas in an air balloon makes the balloon rise due to the principle of buoyancy and the behavior of gases. The gas inside the balloon, usually air or helium, is heated by a burner, causing it to expand and become less dense than the cooler air surrounding the balloon.
Here’s how it works:
- Hot air rises: When the gas inside the balloon is heated, its molecules gain energy and move faster. This increased movement causes the gas to expand, occupying a larger volume. According to Charles’s Law, when the temperature of a gas increases at constant pressure, its volume increases. This expansion reduces the density of the gas, as density is defined as mass per unit volume. The gas inside the balloon becomes less dense than the cooler air outside.
- Buoyant force: In any fluid, including air, objects will experience an upward buoyant force if they are less dense than the fluid they are in. This is a principle known as Archimedes’ Principle. The less dense, heated gas inside the balloon is displaced by the denser, cooler surrounding air. Since the buoyant force pushing up on the balloon is greater than the weight of the balloon (which includes the envelope, the gas inside, and the burner), the balloon rises.
- Comparing densities: For the balloon to lift off, the total density of the balloon (gas + envelope) must be less than the density of the surrounding air. Heating the gas inside reduces its density, making the balloon lighter than the air around it, thus enabling it to rise.
In summary, heating the gas in the air balloon causes it to expand and decrease in density. This change in density creates a buoyant force greater than the weight of the balloon, allowing it to rise into the air.
