What everyone needs to know:
You need to know the main types of energy stores such as kinetic, thermal and gravitational potential. Within a system, you need to be able to describe energy transfers such as chemical to thermal.
Note that energy can be transferred or dissipated but it cannot be created or destroyed.
You need to be able to calculate changes in energy due to heating, work done by forces and the work done when current flows through a conductor. You need to calculate the change in energy for:
A moving object (kinetic energy): Ek = ½ m v2
A stretched spring (elastic potential): Ee = ½ k e2
Lifting from ground level (change in GPE): Ep = m g h
Extra topics needed for the Higher papers:
In this topic, there is nothing extra for the higher papers, the questions will just be more challenging.