You might have experienced that on windy days it is difficult to keep the cycle steady. The cycle tends to move in the direction of the wind. It is one these days that we feel the pressure of air. On any other day the pressure of air is rarely felt. If the pressure inside and outside a body is same there is no effect on the body. If you have filled air into a cycle tube more than it can handle, it bursts. It is because the pressure inside the tube is relatively higher than the outside pressure. Do you know what will the case if the outside pressure is very much in excess relative to the inside temperature? We shall try out an experiment to try for ourselves.
To understand the pressure of air
- An electric heater to heat water
- A pair of tongs
- A big sauce pan filled with cold water
- Aluminium can
- Drop a tablespoon of water into the Aluminium can.
- Place the can on the heater and heat it. You will see water vapours coming out of the can.
- Take the can from the heater using tongs and place it upside down in the saucepan.(the opening of the can should face the water, watch the video.)
- The can collapses instantly.
The can collapses with immediate effect.
Why did the can collapse?
As the can was being heated, the air inside the can was pushed out by the vapour. As soon as the can was put in cold water, the vapors condensed instantly creating an area of vacuum inside the can. Since the pressure outside the can is significantly higher it crushed the can.