Hot Air Balloons – EXPLAINED!!!

Seriously guys, let’s practice applying some of these laws to every-day

scenarios!

Use Charles’ Law and KMT to explain the science behind hot air balloons

Getting the balloon into the air:• Burners heat up the balloon by producing a

flame. The temperature inside the balloon ↑.• As temp ↑, so does the average kinetic energy

of the gas particles. Kinetic molecular theory says that as temp ↑, the speed of the gas particles ↑

• Gas particles are moving faster and collide more. These collisions exert more force on the walls of the balloon

• Charles’ Law comes into play now... Because of the fast-moving gas particles, the forces exerted by them on the lining of the balloon causes to expand

• As temperature increases, so does volume!!!

Keeping the balloon afloat in the air• As the volume of the balloon increases, it creates

lift. But as you move up towards the sky, gases continue to escape from the “hole” of the balloon and get colder around that area.

• This slows down the particles and this creates a ↓ in volume. The slowing down of the particles (they come closer together) = denser = sinking

• Balloon must be continually heated with each pull of the burner in order for it to stay afloat

Getting the balloon back down on the ground:• A valve at the top of the balloon is released,

allowing some of the hot gases to escape• The opening of the valve allows exterior cold

air to come in particles slow down even more, and volume decreases

• Allows for balloon to sink back to the ground at a safe rate of descent