Pascal's Law

You may have heard of Blaise Pascal because of the basics on pressure which you picked up in school. True, Pascal's famous name happened to become the unit for pressure. While his discovery was definitely important, there is another law that he discovered which has affected us in more ways than we can imagine. Known, as the Pascal's law, it essentially says that if you apply pressure in a fluid (that is confined), the same pressure will be applied throughout the fluid equally.

Would you believe me if I told you that when I said fluid, I even meant air? I am sorry if you don't because fluid can generally mean air when you are in the world of Physics. Renew your mind, my friends; you must accumulate much patience to deal with Physics. What seems unreal is often real. That's where the mystery lies.

Pascal's principle might not sound groundbreaking, but it actually has been groundbreaking metaphorically speaking and literally speaking. Without this principle, cars could not have possibly existed. Are you really into cars? You probably will get the technical details on my elaboration. A car runs because fuel is being combusted inside that eventually powers it up and allows it to move. What does the combustion do? It creates pressure that pushes on these things called pistons. Imagine them as dumbbells. Now, there are these chambers known as hydraulic chambers. As hydra- implies, they contain water. Think of an airtight box full of water. Now these pistons are on either side of the hydraulic chamber, right opposite each other. They can go inside the chamber and come out, without water leaking out (Keep the principle in mind, the fluid has to be confined so it cannot leak out). Now imagine a force pushing the piston on the right into the hydraulic chamber. That's going to increase the pressure inside. Why? Imagine taking a balloon and squeezing it. It's going to feel pressure, just like the chamber.

Now let the drum roll begin! Here comes Pascal's law. The same force that the piston applied to the hydraulic chamber was transmitted throughout the chamber and at the next piston, which was originally inside the chamber. The pressure that was applied on the second piston pushed it out of the chamber and into its next target. This could be your brakes or maybe another set of pistons and hydraulic chamber. This keeps happening all over the car and allows it to run. As for the literal aspect of 'groundbreaking', machines like cars that break the ground to dig holes use this same principle. You've got to be grateful to Pascal for this one! No more old fashion walking for us. Then again, it's also Pascal's fault that we're so spoilt. That, however, was not the point. The implications of Pascal's laws are tremendous.

Imagine sitting one corner of your house and creating a similar piston system like the one mentioned above. This time, instead of a chamber, think of a zigzagging pipeline (filled with fluid) going to the other end of your house. Can you imagine that if you apply pressure to piston near you, the same pressure would be transmitted all the way to the last piston? Now right in front of the last piston, put a button for an alarm. Wouldn't that be a nice emergency alarm? Of course, that is not the most profound idea, but it works to make my point.

If you have not been convinced about the ingeniousness of Pascal, let me ask you this. If you go to a kid's birthday party, do you expect it to be decorated with deformed balloons? Of course not; Pascal's law reminds us that the gas in the balloon exerts equal pressure throughout a balloon. This allows it to retain the shape that we know and love it for.