Explaining changes of pressure
I can explain the effect of a temperature change or a change in volume on the pressure of a fluid.
Explaining changes of pressure
I can explain the effect of a temperature change or a change in volume on the pressure of a fluid.
Lesson details
Key learning points
- The pressure of a gas in a container increases if the temperature or amount of gas increases, or volume decreases.
- Increasing temperature increases the speed of particles in a gas.
- Pressure × volume = constant (pV = constant).
- When a gas expands, its particles do work on the surrounding air.
- Doing work on a gas can increase its temperature.
Common misconception
Pressure is a weight or a force; and pressure has a preferred downwards direction in a liquid or gas.
Use the particle model to provide opportunities for pupils to explain the causes of pressure in a gas that is in a container, and to explain how the difference in pressure between inside and outside causes an outward force.
Keywords
Particle model - a scientific model using the idea of moving particles to explain the behaviour of matter.
Pressure - caused by a force acting over an area on a surface; it can be calculated using: pressure = force ÷ area
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
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