Changing temperature

Temperature and heat are not the same thing:

• temperature is a measure of how hot something is
• heat is a measure of the thermal energy contained in an object

Temperature is measured in ºC, and heat is measured in J.

Heat energy flows from a hot object to a cooler one. This causes:

• hot objects to cool down
• cool objects to warm up

When heat energy is transferred to an object, its temperature increase depends upon:

• the mass of the object
• the substance the object is made from
• the amount energy transferred to the object

For a particular object, the more heat energy transferred to it, the greater its temperature increase.

The specific heat capacity of a substance is a measure of how much heat energy it can hold. It is the energy needed to increase the temperature of 1 kg of the substance by 1 ºC. Different substances have different specific heat capacities.

Heat capacity of substances

Notice that water has a particularly high specific heat capacity. This makes water useful for storing heat energy, and for transporting it around the home using central heating pipes.