# What is the principle behind the hot air balloon?

## What is the principle behind the hot air balloon?

Hot air balloons are based on a very basic scientific principle: warmer air rises in cooler air. Essentially, hot air is lighter than cool air, because it has less mass per unit of volume. A cubic foot of air weighs roughly 28 grams (about an ounce). If you heat that air by 100 degrees F, it weighs about 7 grams less.

### How does Archimedes Principle relate to hot air balloons?

Archimedes Principle states that the buoyant force on a submerged object is equal to the weight of the fluid that is displaced by the object. Hot air balloons rise into the air because the density of the air (warmer air) inside the balloon is less dense than the air outside the balloon (cooler air).

What do boats and hot air balloons have in common?

In a word: buoyancy. Hot-air balloons float in the sky for pretty much the same reason that boats float on the sea. That means the density of the air in the balloon can change while the pressure inside and outside is essentially the same.

How do hot air balloons create lift?

Hot air balloons work because hot air rises. By heating the air inside the balloon with the burner, it becomes lighter than the cooler air on the outside. This causes the balloon to float upwards, as if it were in water. Obviously, if the air is allowed to cools, the balloon begins to slowly come down.

## Which gas laws apply to hot air balloons?

The operation of a hot air balloon depends on Charles’ Law, the Ideal Gas Law, and Archimedes’ Principle. The operator first ignites a propane burner to fill the balloon with air. As the air continues to heat up, it expands, according to Charles’ Law: V∝kT .

### How is the buoyancy of a hot air balloon created?

Source: http://www.flickr.com/photos/walkadog/3897126692. The basic principle behind hot air balloon physics is the use of hot air to create buoyancy, which generates lift. A hot air balloon consists of a large bag, called an envelope, with a gondola or wicker basket suspended underneath.

Which is lighter a hot air balloon or a cool air balloon?

Hot air balloons are based on a very basic scientific principle: warmer air rises in cooler air. Essentially, hot air is lighter than cool air, because it has less mass per unit of volume. A cubic foot of air weighs roughly 28 grams (about an ounce). If you heat that air by 100 degrees F, it weighs about 7 grams less.

How does the pilot of a hot air balloon work?

To lift the balloon, the pilot moves a control that opens up the propane valve. This lever works just like the knobs on a gas grill or stove: As you turn it, the flow of gas increases, so the flame grows in size. The pilot can increase the vertical speed by blasting a larger flame to heat the air more rapidly.

## How is the stability of a hot air balloon determined?

This is what is meant by unconditional stability. For a hot air balloon, the upward buoyant force acting on it is equal to the weight (or mass) of the cooler surrounding air displaced by the hot air balloon.