Pressure
Science: KS3, topic 3.2.9
Pressure
Pressure is caused when particles in gases or water hit the side of containers. The unit is Newton per Metres2 or N/m2, but also Pascals. One N/m2 is equal to 1 Pascal (Pa).
Pressure
- In a gas, particles are moving in all directions and at different speeds.
- If they hit the sides of their container or walls, this causes pressure.
- This is the same for water pressure.
- A greater number of collisions means an increase in pressure.
Calculating pressure
- To calculate pressure, you must use the equation:
- Pressure = force ÷ area.
- The units are:
- Pressure: N/m2.
- Force: N.
- Area: m2.
- 1 N/m2 is equal to 1 Pascal (Pa).
Area and pressure
- The larger the area in contact with a force, the lower the pressure.
- So a sharper knife will cut through a carrot easier than a blunt knife because of its smaller surface area.
- A smaller surface will increase the pressure.
Test yourself on Pressure
What are the units of pressure?
Select the true statement in each pair.
A diver swims deeper into the sea, so more water particles collide with the diver's body every second. What happens to the water pressure on the diver?