HERE'S HOW
Lay a 12-inch ruler on the edge of a table so that about a third of the ruler extends over the edge. Place several large sheets of paper, such as newspaper pages, over the ruler. Hit the ruler sharply to try to make the paper fly into the air. It can't be done!
WHY?
Air has weight. Because the paper is large, it has a lot of surface area for air to rest on. The air pushes down on the paper with such force that it's difficult to move it with the ruler. Pressure caused by the weight of the surrounding air is called atmospheric pressure.
UP IN THE AIR »
Illustration by David Bamundo
Text by Julie Vosburgh Agnone
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