Year 7 - Science
Reflecting and absorbing sound
Sound, light and vision
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
This unit explores sound and light waves, including frequencies, echoes, reflection, absorption, and the need for a medium for sound to travel. It also compares light and matter waves, investigates light transmission and colour, and examines wave properties and effects.
Lesson Summary
You will learn to describe factors that affect how much sound a material or object might reflect or absorb, and explain ways to reduce noise.
Key Notes
- Sound reflects from hard surfaces. An echo is when a sound is heard again after reflecting and travelling back.
- Smooth, flat surfaces help to produce echoes. Irregular surfaces reflect sound in many directions, spreading it out.
- The particles of harder materials are held together by stronger forces so sound waves can't make them vibrate much.
- Soft surfaces absorb a lot of sound because sound waves transfer energy by making the particles in them vibrate.
- Noise (unwanted sound) can be reduced by using soft materials to absorb it or hard materials to reflect it.
Vocabulary To Learn
- reflect: to 'bounce' off a surface
- echo: when a sound is heard more than once because sound waves have reflected back
- transmit: to pass into and through a material
- absorb: materials that absorb sound reduce the vibrations of the air (as sound is easily transmitted to/through them)
- noise: unwanted sound
Common Mistakes To Avoid
- Pupils often describe an absorbing surface as trapping a sound and do not correctly describe how the vibrations of air particles are reduced by making particles in a surface vibrate more.
3 Quick Questions (With Answers)
1. Explain the scientific idea in this lesson using two key points.
Sound reflects from hard surfaces. An echo is when a sound is heard again after reflecting and travelling back. Smooth, flat surfaces help to produce echoes. Irregular surfaces reflect sound in many directions, spreading it out.
2. Define this scientific word and use it in context. 'reflect'
to 'bounce' off a surface. Include the word in a full scientific explanation, not as a single label.
3. Correct this common scientific misunderstanding.
Mistake: Pupils often describe an absorbing surface as trapping a sound and do not correctly describe how the vibrations of air particles are reduced by making particles in a surface vibrate more. Correction: Provide opportunity for pupils to describe how vibrations of air particles are reduced when sound waves make particles in a surface vibrate more.
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