Pascal's Principle

by Emily B. and Emily M.

Table of Contents

1. What is Pascal's Principle?2. Using Pascal's Principle3. Background on Pascal4. Resources

What is Pascal's Principle?

Pascal's Principle is when force is applied to a confined fluid and the change in pressure is transmitted equally to all parts of the fluid (Science Explorer). This means a liquid in a container will exert the same amount of pressure everywhere in the container. This can be explained easily. In the picture below, figure 1, the small piston pushes down on the enclosed fluid. When this happens, it applies that force everywhere in the container. This pushes up the large piston, even though it;s bigger, because it is applying the same force on every part of the piston the fluid touches (Liquids and Gasses).
Figure 1
Figure 1

Using Pascal's Principle

There are many ways to use Pascal's Principle. One big way is in car brakes. In car brakes, there is a container/tube shaped like the one in figure 1. When a driver hits the brakes, they are putting pressure on the whole tube. This pushes the large piston, causing the car to come to a stop. The more pressure you put on the brake pedal, the more pressure you put on the tube, and the more pressure is put on the brake, causing the car to either come to a quick, or slow stop. (Liquids and Gasses) Pascal's Principle is used for other things too.

Background on Pascal

Who was Blaise Pascal? Pascal was a French mathematician, who known for great things. This includes his studies in Probability/Chance (Liquids and Gasses). Also for creating the frist counting machine, in which many people think of as the frist computer. There is even a metric unit (used for measuring preasure) called the Pascal, in honor of his acheivments in the study of air and water presure (Encyclopedia of Science).The video below explains more on Pascal's Life.


1. Chemical Blocks: Science Explorer. Upper Saddle River, NJ, USA: Pearson Education, Inc., 2009. Print.2. Newton, Davied, and Rob Nagel. Encyclopedia of Science. 2. NY, USA: Thomas L. Roming, 1998. Print.3. Fleisher, Paul. Liquids and Gasses: Pricipales of Fluid Machanics . Minneapolis, MN, USA: Lerner Publications Company, 2002. Print. All Pictures off of