- Water and air are bad conductors of heat.
- The upwards and downwards movement of molecules of water or air is called Convection current.
- The increase in the volume of water as its temperature is lowered from 4°C to 0°C is known as “Anomalous expansion” of water or
- peculiar behavior of water.
- Solids, liquids and gases are expand on heating is called “Thermal expansion”.
- There are three scales of temperature measurements i.e. Celsius scale or Centigrade scale, Fahrenheit scale and Kelvin scale.
- The expansion in length of metallic objects is called “Linear expansion”.
- Liquids expand on heating and contract on cooling like solid.
- Gases also expand on heating contract on cooling.
- The electric fire alarm works on the “Principle of expansion”.