Heat Capacity

Heat capacity is defined as the amount of heat that something must give away in order to cool down 1^oC. Since heat can be both lost and gained by an object, heat capacity is also the amount of heat that something must absorb in order to got 1^oC hotter.

In English, the heat capacity tells us how easy or difficult it is to change the temperature of something. The higher the heat capacity, the harder it is to warm something up or cool it down. A cup of cocoa has a relatively high heat capacity, while a stack of toast has a relatively low heat capacity.

Objects with large heat capacities are sometimes called heat sinks, because a great deal of heat can be “sunk” into them without dramatic changes in temperature. The processor in your computer has a heat sink attached, to absorb the large amount of heat produced without allowing the circuits to get so hot that they won’t function problem. There are lots of other examples of heat sinks in our everyday life. A few are explored here.

Heat capacity depends on the material from which the object is constructed and its mass. Thus a larger mug of cocoa has a higher heat capacity than a small cup of cocoa.

That also means that it is possible to have a huge pile of hot toast and a very small cup of cocoa, such that the heat capacity of the toast and therefore, its ability to warm you, was greater than that of the cocoa.

For that reason, we often choose to separate out those factors. Thus, heat capacity can be broken into two separate but important properties. The first of these is simply the mass. The second is a factor that depends on the internal properties of the material called specific heat capacity or just specific heat.