4.2 describe energy transfers involving the following forms of energy: thermal (heat), light, electrical, sound, kinetic, chemical, nuclear and potential (elastic and gravitational)

This basically means what are the types of energy...

Electrical energy > whenever a current is flowing
Light energy > from the sun, light bulbs etc (when light is 'given off')
Sound energy > noise, e.g. when you should, or from a loudspeaker
Chemical energy > in foods , fuels, batteries etc
Kinetic energy > movement (everything moving has kinetic energy)
Nuclear energy > released nuclear reactions (and nothing else)
Thermal energy > this flows from hot objects to cold ones (also known as heat energy)
Gravitational Potential Energy (GPE) > anything that has the potential to fall has GPE. E.g. if you hold a tennis ball, it has GPE.
Elastic Potential Energy (EPE) > anything that can stretch has EPE. For example an electric band or a spring

NOTE: GPE, EPE and chemical energy are forms of stored energy, because the energy is not doing anything (unlike kinetic energy, for example), its just sort of there.