Describe a simple experiment to illustrate that air exerts pressure.

EXPERIMENT: Take a tin-can having an airtight cap (screw cap). Remove cap and boil some water in it,so that steam comes out and in this way air from inside goes out. While boiling replaces the cap and allows it to cool. Vapours inside condense and form water creating vacuum above them. We see the can crumbles due to air pressure from outside. This proves that air exerts pressure.