5-SLG-4

Outcomes

• Pupils talk about the increase of speed and kinetic energy of particles with temperature
• Pupils can begin to see the link between pressure, temperature and volume

Specification References

• 5.13 understand that an increase in temperature results in an increase in the average speed of gas molecules
• 5.14 understand that the Kelvin temperature of the gas is proportional to the average kinetic energy of its molecules
• 5.15 describe the qualitative relationship between pressure and Kelvin temperature for a gas in a sealed container

Starter

Recap work from previous lessons on Brownian motion and converting to Kelvin temperatures

Main Body of Lesson

Can link into work done with the mechanical model in previous lessons about how particles moving faster exert more pressure. Can introduce the idea of a distribution of particle speeds and that we tend to comment on the average speed of the particles. If the speed is increasing then the kinetic energy will be increasing too. Now is a good time to recap the KE equation and rearrange it. Could add some questions giving the energy of a molecule and use this to find it's speed or work the other way. This also gets pupils using very small values and is good standard form practice. If you finish all of that then there is a nice PHeT app which introduces pressure and temperature: http://phet.colorado.edu/en/simulation/gas-properties . This introduces the work for next lesson. There are plenty of things you can vary, have pupils predict what will happen if you change the temperature of the mass of gas or the volume.