Conduction in gases
Read the thermometers and record the temperatures at A and B in a suitable table.
Switch on the heater and leave for eight minutes.
Read the thermometers again and record the temperatures at A and B.
Results
| Thermometer | A | B |
| Initial temperature in oC | 20 | 20 |
| Final temperature in oC | 46 | 23 |
| Thermometer | Initial temperature in oC |
|---|---|
| A | 20 |
| B | 20 |
| Thermometer | Final temperature in oC |
|---|---|
| A | 46 |
| B | 23 |
Conclusion
Heat has not conducted easily through the trapped air to position B.
This shows that trapped air is a poor conductor (or good insulator).
Applications
Trapped air is a good, natural insulator.
That is why we wear layers of clothes when it is cold.
A string vest keeps you warm because it traps a layer of air between your skin and your shirt.
Additional layers provided by shirt, fleece and coat help to trap more air, providing more insulation.
Hair is a good insulator too, trapping air between individual hairs on your head.
Wearing a woollen hat on top helps to trap even more air.
Each layer of trapped air helps us to stop losing heat energy by conduction.
Fur, feathers and wool trap air between individual stands and fibres.
This helps animals such as sheep and polar bears and birds like robins, insulate themselves against cold winter conditions
