Break a Ruler Using Newspaper and Atmospheric Pressure
In those rare moments when we actually think about the air around us, we typically think of the oxygen that allows us to breathe. But did you know that oxygen makes up only 21% of the Earth’s atmosphere? The rest is composed of nitrogen, argon, carbon dioxide, varying amounts of water vapor, and trace amounts of many other gases. These gasses form our atmosphere, a layer of air that is 80 miles thick. Like any type of matter, the gases in air have mass, and since Earth’s gravity causes the atmosphere to press down on the Earth’s surface, we call this force atmospheric pressure. Pressures are expressed in force per unit area. At sea level, the 80-mile column of air exerts a pressure of 15 lbs per square inch (psi). We don’t usually notice the earth’s atmosphere pressing down on us, because we’ve lived with it our entire lives! However, this cool science experiment can help us appreciate just how powerful air pressure is.
How can we see and feel the power of air pressure?
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