Cotton wool acts as a good thermal insulator. It is made up of many cotton fibres that are twisted together to form a material that can be pulled apart easily or compressed. The diagram shows the structure of cotton wool. Why does cotton wool act as a good thermal insulator?
- AEach thread is very thin.
- BIt has a large surface area because it is made of many threads.
- CIt has a low density because of the trapped air.
- DIt traps air and prevents convection.