Structured Questions
Unit 14
Waves
Marking Guide
These are model answers, which are not designed to be prescriptive. Good answers should contain the
key science ideas covered in the model. Section ‘d’ questions in particular are intended to stretch
students, and novel applications of knowledge should be rewarded.
The level icons are a guide to which level a student will attain if they consistently answer questions of
that level correctly.
Marks
Level
1
1a (i) A few metres per second.
1
(ii) A ripple tank.
1
1b (i) The molecules move up and down.
1
(ii) A disturbance.
1
1c The molecules on the surface of the ocean only move up and
down, not from side to side. The disturbance travels across
the surface of the water, forming a wave, but the molecules
do not. So the boat moves up and down, not from side to side.
3
1d (i) Water waves can be reflected from a barrier in the same
way as light waves can be reflected from a mirror.
2
Water waves can pass through each other, just as light
waves from torch beams can pass through each other.
(ii) Light waves travel many times faster than water waves.
Water waves require a medium to travel through; light
waves do not.
2
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Structured Questions
Unit 14
Waves
Marking Guide
2
2a
2
2b
1 for crest (or peak)
1 for trough
1 for distance label
2c
2
2d
2 for diagram
1
These waves will cancel each other out.
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Structured Questions
Unit 14
Waves
Marking Guide
3
3a (i) To make waves, the bar should be vibrated up and down.
(ii) The waves will be reflected by the barrier.
1
1
3b
1 for straight lines
parallel to vibrating
bar, 1 for making
them evenly
separated
2 for reflected lines
perpendicular to
incident lines, with
same separation
3c (i) Incident waves.
(ii) Reflected waves.
1
1
The water waves travel in straight lines and are reflected at an
angle off the barrier, so this is exactly like light reflecting from
a mirror.
3d
1
1 for normal
1 for arrows
showing direction
of travel
1 for each angle
© Smart Learning Ltd 2014 – For use by purchasing institution only.
Structured Questions
Unit 14
Waves
Marking Guide
4
4a Sound waves cause particles to vibrate backwards and forwards along the
direction of the wave. We call them longitudinal waves.
2
Light waves and water waves cause vibrations up and down across the
direction of the wave. We call them transverse waves.
4b
2
4c Energy and information.
2
4d Sound waves can cross over each other, and our ears can detect all the
different vibrations these sound waves cause. So we can hear each and
every source of sound (each instrument in the orchestra).
3
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