Squeezing the Air

Squeezing the Air

You will need: Newspaper, ruler.

We live in a vast 'sea' of air on this planet, and it exerts pressure around us and on our bodies all the time.

Scientists have measured this pressure and find that it amounts approximately to 15 pounds of pressure for every square inch. When you think of the number of square inches over your body you may well wonder why you are able to move around so easily. In fact, it is only possible because our wonderful bodies have been so adjusted that we neither notice this pressure nor suffer any ill effects from it. Indeed, if there were no air we would die.

An easy way of proving the presence of air pressure is to cover a ruler with a large sheet of newspaper so that one end of the ruler projects over the table, as shown in the picture.

Now bring your fist sharply down upon the free end of the ruler. The air pressure on the large area of the newspaper will dislike being squeezed upward so suddenly and it will hold the ruler to the table so that it will resist the blow with your fist. If you strike downward with sufficient force you can even snap the ruler, without tearing the newspaper.