PASCAL’S PASCAL’S PRINCIPLEPRINCIPLE

Chapter 11 Section 3Chapter 11 Section 3

Lets Review…Lets Review…What is pressure? What is pressure?

What is the equation for pressure? What is the equation for pressure?

What causes fluid pressure?What causes fluid pressure?When you catch a deep-sea fish, why

does its eyes pop-out?Why do your ears pop on an airplane

or up in the mountains?

Pascal’s PrinciplePascal’s PrincipleWhen force is applied to a confined When force is applied to a confined

liquid, the change in pressure is liquid, the change in pressure is transmitted equally to all parts of the transmitted equally to all parts of the

fluid.fluid.

Draw a bottle of water with arrows to Draw a bottle of water with arrows to illustrate the regular exerted pressure. illustrate the regular exerted pressure.

Then draw a water bottle that you squeeze. Then draw a water bottle that you squeeze. What happens to the pressure? What What happens to the pressure? What

happens if you open the top?happens if you open the top?

How does Pascal’s Principle explain what How does Pascal’s Principle explain what happens if you squeeze a water bottle?happens if you squeeze a water bottle?

A force applied to one section A force applied to one section of an enclosed liquid at rest of an enclosed liquid at rest

will be transferred to the will be transferred to the entire liquid with the same entire liquid with the same

amount of force.amount of force.

Hydraulic SystemsHydraulic SystemsA force applied to one piston increases A force applied to one piston increases

the fluid pressure throughout the the fluid pressure throughout the fluid.fluid.

If the second piston has a larger If the second piston has a larger surface area, the force is surface area, the force is multipliedmultiplied!!

Pressure = Force/AreaPressure = Force/Area

Force/Area = Pressure = Larger Force/Area = Pressure = Larger Force/Larger AreaForce/Larger Area