When the spark plug ignites the fuel, there is an explosion, which makes the piston move down with great force.

As the camshaft rotates, the cam pushes the intake valve downwards, which allows the fuel to enter the cylinder.

When the piston moves away from the valves, it creates a vacuum in the cylinder, which sucks the fuel in.

When the piston moves up towards the valves, it puts the fuel under high pressure, which helps the gases to expand rapidly after ignition.

As the cam pushes the exhaust valve down, the piston moves up towards it, which forces the burnt gases out of the engine.

This is a scientific principle refrigerators are based on:

For every action there is an equal but opposite reaction.

This is a scientific principle refrigerators are based on:

When you compress a gas, it condenses. When you decompress a liquid, it evaporates

This is a scientific principle refrigerators are based on:

The upthrust is equal to the weight of the displaced fluid.

This is a scientific principle refrigerators are based on:

As a gas condenses, it gives out heat. As a liquid evaporates, it absorbs (takes in) heat.