# How to show the difference between force and pressure

• A force can be a push or a pull. When a force is exerted on an object it can change the object's speed, direction of movement or shape.

• Pressure is a measure of how much force is acting upon an area.

• Pressure can be found using the equation pressure = force / area. Therefore, a force acting over a smaller area will create more pressure.

## How do we measure pressure?

Mass is a measure of how much matter there is; force is the pull of the Earth's gravity on that mass. Each kg of mass is pulled down by the Earth with a force of 10 N.

We all have a mass (kg). To convert this to force (N) we multiply the mass by 10.

We can then calculate pressure using: pressure = force ÷ area.

If you stand on one foot (rather than both feet), the pressure exerted would be twice as great. Similarly, a stiletto heel creates far more pressure than a normal shoe.

## Did you know?

A person wearing a stiletto can exert more pressure on the ground than an army tank! This is because the army tank uses caterpillar tracks to spread its weight (and therefore force) over a larger area, in order to reduce the pressure. If it didn't, it would sink into the ground and wouldn't get very far!

## Who uses knowledge of forces and pressure?

When structural engineers and architects design and construct a building, they need to make sure the foundation is strong enough and that the building doesn't sink into the ground.