Question

When we blow air into a balloon it expands.

Answer 1

When a balloon is blown up, the air pressure inside the balloon slowly becomes greater than the air pressure outside the balloon. Since the balloon is made of rubber and is expandable, it grows larger and larger. When the balloon is popped, the air escapes instantly. The sound heard is due to the molecules of air inside the balloon coming into sudden contact with the molecules of air outside the ballon .

Answer 2

Answer:

It expands because the pressure inside the balloon is larger than the pressure outside the balloon and the balloon is made from a flexible material.

Explanation:

Gas will always take as much space as is available. If a lot of gas molecules are trapped in a small space, they will collide with the walls more often. That is perceived as "pressure".

If space is larger, the molecules fly long before they hit the wall and the pressure is lower.

If you blow air into a ballon, you add air molecules into a contained space.

However, the ballon is flexible. Its material (rubber) is made from many long molecules (called polymers) that stick to each other. When you pull them apart, they will move, but pull back together.

If we blow more and more air into the balloon, the molecules hit the inside of the rubber more and more often, pushing them out and apart. The balloon will expand. Eventually, the long rubber molecules will break, causing the air to flow out of the balloon fast. So fast that we call it an explosion.