Crank the Engine

Pistons and crankshafts within car engines interact to create movement in a car.

How it works

Turn the handle and watch as pistons move up and down inside cylinders to turn the engine's crankshaft below.

Things to try or ask around the exhibit

• What parts can you see moving inside the engine?
• When each piston moves, what else moves in response?

Background

Each cylinder is usually enclosed and as well as containing a piston, each cylinder contains a mixture of air and petrol fumes. A spark ignites the petrol inside the cylinder, so it explodes and forces the piston down the cylinder.

As each piston shoots down in succession with split second timing, they each turn the crankshaft in quick succession. The crankshaft keeps turning and drives the piston back up the cylinder. This powers the car’s engine.

Finding the science in your world

Cars tend to have four, six or eight cylinders that rotate their crankshafts. More cylinders give greater engine power as well as higher fuel usage.