The Secret of Compressed Air | Science of Stupid: Ridiculous Fails
Air is a remarkable substance. Not only does it allow us to breathe, which I think we can all agree is a good thing, but if you compress it and contain it, you can have loads of fun. Like defying the laws of physics. Or for wacky furniture. Whack! See?
The secret to understanding and using compressed air is to realize that all it wants to do is stop being compressed air. It wants to escape, and in so doing, air teaches us valuable science on pressure differentials and conservation of energy. If air in one part of a container is compressed, it will apply pressure to all other parts until all areas are the same pressure. This is due to conservation of energy.
When a container of compressed air is open to the atmosphere, the high pressure inside equalizes with a lower pressure outside, producing a force as the air escapes. And whatever is containing the compressed air needs to have the material strength to withstand the pressure differential; otherwise, it will fail. To sum up, pressure changes will be transferred to all parts of the container. Give something at high pressure an opening, and it will take it and escape with force. And finally, whatever you do, make sure the container you're using is strong enough. So now you know.
But do our researchers know? Yes, they do. The jumper has cleverly demonstrated a basic pneumatic system. He adds kinetic energy with his jump, which causes a pressure change in the bag. And due to conservation of energy, the kinetic energy is transferred to her, and she then transfers that same energy to the bedside table via her head.
How about something a little more high tech? Surely these amateur rocket engineers understand pneumatics. Turns out, they don't. The young researcher was trying to compress air by jumping on the pump. Unfortunately, he misses. But Oliver does it. When the pump is pressed, the pressure differential created applies a force that launches the rocket. Good to get a closer look at the physics.
Understanding the science allows you to take advantage of the science. Like building a beach trampoline. Fun times. Yeah, less fun times. The membrane of the beach ball didn't have the material strength to contain the higher pressure produced by our more sure-footed researcher.