Air Pressure Newspaper Experiment

I have seen this experiment in many books, but never from the viewpoint of a teacher who actually does this experiment. First you need a few sheets of newspaper that you can open and set flat on a large desk top. You should bend the crease back on the newspaper to get it as flat as possible when you place it flat on the desk top. If you use less than the whole opened newspaper this experiment may not work as well. It is better if there are several sheets of paper on top of one another or it may tear. If the crease is not taken out it will let air under the paper more quickly. You then put a "paint" stick under the newspaper at about the center point with about 1/2 of the newspaper stick out over the edge of the desk. Then if you lightly but quickly hit the protruding end you will feel the great resistance that the air above the newspaper exerts and keeps you from bending the stick quickly down. The stick may actually break if you hit it hard and fast.

Many of the versions in other books say to use a "ruler" but you should NOT use a ruler. Many rulers today have a wire edge. If the ruler breaks the wire edge can cut you or whoever hits the stick. I use wooden paint sticks that I get at lumber stores. They give the sticks out free and I can get dozens to use for this experiment. These sticks are also made of a fairly soft wood and work well for this experiment. If you are working with older students you should have them wear goggles. If they do break the stick the pieces can fly around. When I do this I move the students near the front of the class back and out of the way. Small children should not be hitting the stick hard attempting to break the stick. Their tiny hand bones could break. They can quickly push on the stick and feel the pressure. Above the paper there is actually about two tons of air (about 15 pounds per square inch.) It will move out of the way if the stick is pushed slowly, but can not move out of the way quickly.

In a high school class there is no shortage of students that want to come up to the front of the room and try to break the stick, but again be careful you do not want a student hurt by this experiment. I demonstrate this experiment first and have selected one or two students to try this. I warn them about the dangers of using some other wood which could be much stronger. You may want to try this first to see just how much force is required. It is not necessary to hit it so hard that the stick breaks to get the idea of the air pressure on the paper.

One time I had a large football player come up and he wanted to break the stick. His hands were large and muscular and I let him try. He completely missed the stick on the first try which cause a great deal of laughter. Of course he quickly tried again and easily broke the stick and redeemed his honor. In all of the experiments that I did in the classroom I tried to have some that were exciting but made every effort to keep them safe.