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6
Earth physics
6.1 Sound waves
Exercise 6.1 The movement of sound
In this exercise, you will describe the movement in a sound wave.
Focus
1
Zara is playing the violin.
Sofia hears the sound from the other side of the room.
What must happen for Sofia to hear the sound?
Tick (3) one box.
Objects in the room vibrate.
Particles in the air vibrate.
Particles outside the room vibrate.
The air moves from the violin towards Sofia.
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6 Earth physics
2
For each of these statements, write ‘true’ or ‘false’.
Sound travels through solid wood. …………………………
Sound travels through water. …………………………
Sound travels through a vacuum. …………………………
3
Use words from the list to complete the sentence.
vibrate a vacuum solids particles a gas liquids
Sound does not travel though ………………………… because
there are no …………………………
Practice
4
A sound is sent from the bottom of a ship. The sound goes down
through the water, as shown in the diagram.
direction of sound wave
What happens in the sound wave?
Tick (3) one box.
Particles in the water do not move.
Particles in the water vibrate from side to side.
Particles in the water vibrate up and down.
Particles in the water vibrate randomly.
5
Explain why sound does not travel in a vacuum.
…………………………………………………………………………...
…………………………………………………………………………...
…………………………………………………………………………...
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6.1 Sound waves
6
A loudspeaker is playing loud music.
Sofia holds her hand in front of the loudspeaker cone.
Describe what Sofia will feel when the music is playing.
…………………………………………………………………………...
…………………………………………………………………………...
…………………………………………………………………………...
Challenge
7
A slinky spring is stretched across the floor.
One end of the spring is attached to a clamp.
Marcus holds the other end of the spring.
He makes a wave in the spring that models a sound wave.
a
Draw arrows on the diagram to show how Marcus should
move the end of the spring.
b
In the space below, draw how the spring would appear when
modelling a sound wave.
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6 Earth physics
8
The speed of a sound wave in air is 340 metres per second.
The speed of a sound wave in solid concrete is 2950 metres per second.
Use ideas about particles to suggest reasons for the difference in speeds.
…………………………………………………………………………...
…………………………………………………………………………...
…………………………………………………………………………...
9
People who work beside aeroplanes wear ear protection.
Explain why loud sounds can damage people’s ears.
…………………………………………………………………………...
…………………………………………………………………………...
…………………………………………………………………………...
6.2 Reflections of sound
Exercise 6.2 Reflections of sound
In this exercise, you will describe what happens when a sound wave is
reflected.
Focus
1
What is the name for a reflected sound wave?
Tick (3) one box.
sound
vibration
echo
note
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