# Pascal's See Saw

Pressure applied over an area generates a force that can do work. Changing the area or the pressure increases or decreases the force.

## How it works

Push down the narrow piston and watch how the attached, wider piston moves, due to transferred pressure and force over an area.

## Things to try or ask around the exhibit

• Will each piston move the same distance and with the same force?
• Which piston moves higher?
• Is one piston more difficult to push down than the other?

## Background

The two pistons and connecting tubes are filled with air. As you push down one piston, a constant pressure moves through the air. More air is in contact with the wider piston, so it moves with more force (maybe to lift heavy items), but only over a short distance. To raise the wide piston,you need to push the narrow piston down further (but it's easier to push down). This is called magnification of force.

## Finding the science in your world

Pneumatic (air-based) and hydraulic (oil or water-based) pistons are used in many ways.

When a mechanic lifts a car on a hoist, they are putting oil and air under pressure in a hydraulic lift.

When you drive a car, it uses hydraulics and pneumatics to work the brakes and steering.

The next time you see a garbage truck lifting a wheelie bin, or a giant excavator moving piles of dirt, see if you can spot their moving pistons.