Reflecting and absorbing sound
I can describe factors that affect how much sound a material or object might reflect or absorb, and explain ways to reduce noise.
Reflecting and absorbing sound
I can describe factors that affect how much sound a material or object might reflect or absorb, and explain ways to reduce noise.
Lesson details
Key learning 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.
- 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.
Common misconception
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.
Provide opportunity for pupils to describe how vibrations of air particles are reduced when sound waves make particles in a surface vibrate more.
Keywords
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
Licence
This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Video
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