Heat and temperature
Temperature is a measure of condition, i.e. how hot or how cold something is. Temperatures are normally measured in degrees Celsius, although it is still quite common to encounter temperatures given in degrees Fahrenheit. In the Kelvin temperature scale, temperature measurement starts at absolute zero. Cooling systems on liquid-cooled engines are pressurised and the operating temperature is often greater than 100 °C. When materials are heated they expand. The amount of expansion that is produced by a one degree Celsius rise of temperature in a 1 metre length of material is known as the coefficient of linear expansion. Specific means the amount of heat required to produce a change of state in 1kg of substance. Latent heat is involved whenever a change of state occurs. Heat transmission by conduction requires a material medium such as a solid, liquid, or gaseous substance.