With simple everyday components and a little bit of Physics knowledge, you’ll be learning now how to make a simple but astonishing experiment: the air cannon.
Materials you need
- Plastic bucket without handle
- Plastic bag
- Tape
- Scissors or stiletto
The Experiment
Firstly, you have to cut a hole in the bottom of the bucket. This hole must have a smaller diameter than the open side and must be in the centre of the bucket.
After that, tape firmly the plastic bag over the opening that is opposite the hole. Be careful when taping, because the bag can’t contain any air leaks.
Then it’s ready to be played – yes, it can be used as an amazing toy! You only have to make some good targets, like your friend’s hair or some candles, and tap on the plastic so that the air goes outside the bucket.
What about Physics?
The subject being addressed on it is called Continuity Equation. It says that the flux of air inside the bucket is equal to the flux through the exit site, which is given by the product of the velocity in which air is flowing and the area it’s occupying. Therefore, the area is inversely proportional to velocity, so that the fluxes continue being the same both inside the bucket and at the exit orifice. That is to say, as the air occupies a smaller area when flowing through the open orifice, its velocity must be greater at this location so that it equals the flux on the whole process.
A1 . V1 = A2 . V2
Very interesting, isn’t it? To make it even more amazing, watch this video below showing the largest and most powerful air cannon the world has ever seen!
http://www.youtube.com/watch?v=ayaiArVkpA4
Gabriel Alves
Freaking Saturday Life 