
This month the Senior ELP Scientists have been undertaking the Learning Outcome 3 from their Physics Unit, Sound and Music.
They have been Investigating which material blocks the sound best using an experiment described in the linked Powerpoint devised by the pupils to show what they did – and discovered!
We began the lessons by asking why some of our pupils carry ear defenders with them on their wheelchairs and discovered they did this because they may have to sit near fire bells during a fire alarm and their ears need extra protection. We were lucky enough to be allowed a look at some of these defenders and posed the questions
- what were they made from?
- why were the materials important and useful?
We remembered that sound can only be made when something vibrates and that it needs particles to be able to move from one place to another. You can’t hear any noises in space because it is a vacuum – which makes a lot of the Star Wars and Star Trek scenes inaccurate we guess 🙂
Some materials transmit sound waves better than others. Solids work better than liquids and liquids are better than gases! We know sound travels through solids better than gases because we could hear a scratch on a table better by putting our head on the desk. We know sound travels through liquids because we have seen dolphins and whales communicate under the sea.
We were set the challenge of trying to find out what material would make the best sound insulator. The materials we were asked to test included
- foam
- rubber
- cotton wool
- bubble wrap
Our method and results are included in the Powerpoint.
At the end we had to draw a conclusion about which material would be best at keeping out sound and decided that cotton wool would be most suitable because of the results of our experiments. Maybe that’s why Santa moves around so quietly at night…