Describing waves
3 marks · NormalExplain, with reference to energy transfer, how a wave can move along a spring without any part of the spring being carried along with the wave.
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The energy moves along the spring as the wave passes, but each part of the spring only vibrates about its position. The particles do not travel with the wave; they oscillate in place, passing energy along to the next particle.
Also accept: Energy is transferred, not matter; each coil vibrates but stays in its place.
Common mistakes: Saying 'the wave carries the spring along'; Saying particles travel with the wave
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Marking points
B1 · 1 mark · States that energy is transferred along the spring (not matter).
B1 · 1 mark · Describes that particles/coils vibrate about a fixed position.
B1 · 1 mark · Specifies that particles do not move along with the wave.
Worked solution
As a wave travels along the spring, each coil vibrates about its position and transfers energy to the next coil. The coils themselves do not travel along the spring with the wave.