Science Experiment
Vacuum cannon

Have you ever asked you if it's possible to make a cannon at home? Do you know what a vacuum cannon is? A vacuum cannon is a propeller that plays with the atmospheric pressure. This experiment that has been done by some students of the school shows how to make one at home, and the importance of the pressure on propulsion. 

It's necessary to have a vacuum pump (you can see on the next link how to make one at home if you don't have it at home, https://www.youtube.com/watch?annotation_id=annotation_258262&feature=iv&src_vid=CVL99yIB3NQ&v=UkPLu6mgdWA), a PVC tube, aluminum paper, duck tape, a bicycle valve, a ping pong ball and a hammer.

1-.  Make a little hole on the PVC tube to put a little bicycle valve for the posterior introduction of the vacuum pump. 

2-. Put the ping pong ball inside the PVC tube and then cover both tube ends with aluminum paper and duck tape like the photo. (The aluminum paper must not have any hole)

3-. Remove the oxygen from the tube with the vacuum pump. It's recommendable to arrive to 25 in Hg to make more reliable the propulsion. (As the oxygen is removed, the aluminum is being absorbed).

4-. Open a hole in one of the tube with the hammer. 

ATTENTION: Don't stay in front of any of the ends of the tube in case the ball shoots out from the tube to the wrong side. Although is a ping pong ball, the pressure can make a big force of propulsion and it can cause injuries.

When the oxygen is removed from the tube and then a hole is opened, the oxygen enters really fast and pushes the ball to the other side making a hole and making the ball shoot out because of the pressure.

We can see that pressure has an important paper on propulsion since without it, the cannon wouldn't work.

Check the following link to see the video of the experiment! https://www.youtube.com/watch?v=CVL99yIB3NQ

Alejandra Gallardo
4t ESO B