4Energy-5
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Contents
Outcomes
- Pupils understand that thermal energy is transferred in three ways: conduction, convection
- Pupils understand the process of evaporation as a decrease in thermal energy.
Specification References
4.6 recall that energy transfer may take place by conduction, convection and radiation
Starter
Main Body of Lesson
- Emphasise to pupils that "cold" doesn't move - thermal energy always moves from higher concentration (hot objects) to lower concentration (cold objects). You can draw parallels with biological examples that they may be familiar with (e.g. osmosis).
- Explain the processes of conduction, convection and radiation using heat transfers circus.
- Show pupils demonstrations of conduction, convection and radiation.
- Explain the process of evaporation as a decrease in average kinetic energy.
Practicals/Demonstrations
Conduction demonstrations
- Wood/aluminium plates (identical in appearance) with ice cubes - one melts very quickly, one very slowly.
- Rods of different metals (e.g. copper, aluminium) with embedded thermochromic thermometers (or alternatively, covered in wax) can show the progress of conduction.
Convection demonstrations
- Convection tubes; one with potassium permanganate and spirit burner; one with water and glitter.
- Smaller convection tube with can be "operated" by heat from a pupil's hand.