Year 4 Science: Distance from the sound source
Part of the Year 4 Science sound chapter. Chapter overview · whole chapter on one page
Distance from the sound source
The sound source is the thing that makes the sound. When you move further away from the source, the sound gets fainter. This is because the vibrations spread out over a larger area, so less of the sound reaches you.
The table shows how the sound from one drum changes as the distance increases.
| Distance from the drum (m) | How the sound is |
|---|---|
| 1 | loud |
| 5 | quieter |
| 10 | faint |
Key ideas
- The sound source is the thing that makes the sound.
- Sounds get fainter as the distance from the source increases.
- The loudest sound is the one nearest the source.
- Vibrations spread out, so less of the sound reaches a listener who is further away.
Method. Read the table.
- Find the loud row. The loud sound is at 1 metre from the drum.1 metre
- Write the number. So the loudest listener is 1 metre away.1
- Write the answer. 1
Check. The nearest listener hears the loudest sound. ✓
Method. Subtract the nearer distance from the further one.
- Read the distances. The faint listener is 10 metres away, and the loud one is 1 metre away.10 and 1
- Subtract. 10 minus 1 is 9.10 - 1 = 9
- Write the answer. 9
Check. Check: 1 plus 9 makes 10. ✓
Method. Read the pattern.
- Read the table. The sound is loud at 1 metre, quieter at 5 metres and faint at 10 metres.faint
- Write the answer. So as the distance increases, the sound gets fainter.fainter
- Write the answer. fainter
Check. Sound gets fainter with distance. ✓
Watch out
Watch out: a sound that is fainter is not a different sound. It is the same sound, with less of it reaching you because you are further away.
Try it at home or school (with a grown-up). With a grown-up, sit still and tap a drum or a tin gently, first close by, and then from further away across a room. Say whether the sound feels fainter further away. Keep your ears safe, and never make loud sounds close to anyone’s ears.
Exam tip
Grown-up tip. Ask: “Did the sound get fainter when you moved further away? Why?” Let your child explain the spreading out, in their own words.
Exercise 8E Distance from the sound source
Method. Read the quieter row.
- Read the row. The quieter sound is at 5 metres.5 metres
- Write the answer. 5
Check. Five metres is between 1 and 10. ✓
Method. Read the faint row.
- Read the row. The faint sound is at 10 metres.10 metres
- Write the answer. 10
Check. Ten metres is the furthest listener. ✓
Method. Subtract the distances.
- Read the distances. The loud listener is at 1 metre, and the faint listener at 10 metres.10 and 1
- Subtract. 10 minus 1 is 9.9
- Write the answer. 9
Check. Check: 1 plus 9 makes 10. ✓
Method. Read the key idea in section 8.5.
- Read the key idea. Sounds get fainter as the distance from the source increases.fainter
- Write the answer. fainter
Check. Further means fainter. ✓
Method. Read the key idea in section 8.5.
- Read the key idea. The sound gets fainter as the listener moves away.fainter
- Write the answer. fainter
Check. The sound spreads out as it goes further. ✓
Method. Compare the two distances.
- Compare them. 10 metres is more than 1 metre.10 is more than 1
- Decide. So the answer is yes.yes
- Write the answer. yes
Check. Ten is bigger than one. ✓
Method. Look for the loudest sound in the table.
- Read the table. The loud sound is at 1 metre.loud at 1 metre
- Write the distance. So the loudest sound is heard at 1 metre.1
- Write the answer. 1
Check. The nearest listener hears the loudest sound. ✓
Method. Think about the move.
- Think about the move. Ali moves further from the drum, from 5 metres to 10 metres.further
- Decide. Further away means the sound is fainter.fainter
- Write the answer. fainter
Check. Moving further away makes the sound fainter. ✓
Method. Read the table.
- Read the table. The loud sound is at 1 metre, and the faint sound is at 10 metres.loud at 1 metre
- Decide. So Ruby is not right.no
- Write the answer. no
Check. Sound is loudest near the source. ✓
Method. Think about a fair test.
- Think about the test. Only the distance should change, so the drum and the hit must stay the same.stay the same
- Write one thing. For example, use the same drum and the same hit each time.same drum
- Write the answer. Accept any one thing, such as: the same drum, the same hit, or the same listener.
Check. A fair test changes one thing only. ✓
Method. Think about how the vibrations spread.
- Think about the spreading. The vibrations spread out in all directions.spread out
- Write the reason. So less of the sound reaches a listener who is far away.less of the sound
- Write the answer. Accept any sentence that says the vibrations spread out over a bigger area, so less of the sound reaches the listener.
Check. Spreading out makes the sound fainter. ✓