SIMPLIFIED: "7.4: Pressure"

Link: https://phys.libretexts.org/Bookshelves/Conceptual_Physics/Introduction_to_Physics_(Park)/03%3A_Unit_2-_Mechanics_II_-_Energy_and_Momentum_Oscillations_and_Waves_Rotation_and_Fluids/07%3A_Fluids/7.04%3A_Pressure 

Note: The above image is from the original article.

What is pressure? You’ve probably heard of the word before, whether it’s blood pressure or water pressure or even how much pressure you have to do well on a test… well that last one isn’t exactly the same pressure as the first two. In terms of physics, pressure is the amount of force that is being exerted over a certain area. Therefore, if the force is greater on a smaller area, then the pressure goes up. Here is the mathematical formula to calculate pressure: pressure = force divided by area.

Here are some real life examples of how you can use pressure. Think about a thumbtack. There’s the part where you put your thumb and there’s the other sharp end. When you push a thumbtack into a wall or a bulletin board, the force from your thumb gets to the sharp end. Since the area of the sharp end is much smaller than the part where you put your thumb, the pressure becomes greater, hence why there is enough pressure to put a hole in the wall. Looking at the mathematical equation, you can see that if area decreases, then the pressure will increase because area is the variable in the denominator of the fraction. Another example is heels versus just some regular tennis shoes. People wearing heels feel more pressure on their feet because the heel basically concentrates all of the force of their weight over a small area. However, when you are wearing just some regular old tennis shoes, the entire shoe spreads your weight over the whole shoe, which is a larger area. 

The unit for pressure is a pascal. A pascal is equivalent to a newton over meters squared, and the newton represents the unit for force while the meters squared represents the unit for area.