Energy Transfer
Heat energy can be lost from homes in many different places but there are ways of reducing these losses.
In GCSE physics curriculum, there are three ways that heat energy can move:
- Conduction
- Convection
- Radiation
Conduction
As we know energy always moves from hotter objects to colder objects.
In conduction energy is transferred from a particle to particle which means that it will transfer easier if the particles are close together so solids are great conductors. Making air not a very good conductor.
Heat energy is conducted through solids by particles vibrating and passing on the movement to neighbouring particles. Use the diagram with steps above to help you.
In GCSE Physics curriculum, you need to remember conduction does not take place in a vacuum.
Convection
Heat can be transferred from one place to another by convection. Like conduction, this process also involves particles.
Convection is hot gases or liquids rising and cooler gases and liquids sinking to replace it.
When a gas is heated it expands. The same mass of gas occupies a greater volume. As substances heat up the density decreases, which is what makes them float/rise.
This movement of molecules is called a convection current. It can only happen in a gas or liquid where the molecules are free to move around.
In GCSE physics, this is the equation used to workout density:
Density (g/cm3 or kg/m3) = mass (g or kg) ÷ volume (m3 or cm3)
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Drafted by Gina (Physics)