Higher: producing and receiving radio waves

Electrical oscillations produce radio waves

Higher Tier: radio waves can be produced by electrical oscillations. An alternating current repeatedly changes direction in a transmitting aerial. These oscillations generate radio waves that carry energy away from the aerial. The frequency of the radio waves is the same as the frequency of the electrical oscillations producing them. The graph shows how the current varies with time; it is not a picture of the aerial moving up and down. An aerial and its radio wave are different parts of the process: charge oscillates in the aerial while the electromagnetic wave travels away.