(New tips are continually added to these pages. Check back in a few months' time for more)

TOPIC 7: Thermal Properties

Tip 1:

Specific Heat Capacity

Let's look at Q = MCT
Q is the amount of Heat or Energy (measured in Joules), you need to pump into an object with mass M and specific heat capacity C, in order to raise its temperature by 1 Degree Celsius or Kelvin.

An object that has a higher specific heat capacity C will therefore be more difficult to heat up than an object with lower specific heat capacity (if both have the same mass M).

Have you tried boiling Campbell Cream of Chicken soup? (You should try that). It takes a very very long time to heat up, as compared to water. Because Campbell soup has a very high specific heat capacity, and it needs much more Q to raise its temperature by T (from room temperature to boiling point).

In the above example, we assume that both substances being compared (Campbell soup and water) have the same mass, but if they have different masses, then we need to consider that too. Of course it takes a longer time to heat up a swimming pool of water than to heat up a small can of Campbell soup, even though Campbell soup has higher specific heat capacity.

Tip 2:

Specific Latent Heat of Fusion/Vaporisation

As regards latent heat of fusion/ vaporisation formula (Q = ML), Q is the amount of energy needed to melt/ boil off completely a mass M of a substance (eg. water). So if a substance has a high latent heat of fusion/ vaporisation, then it will take much more energy (Q) to melt/ boil it, compared to another substance with latent heat of fusion/ vaporisation, provided both have the same mass. (Note that while melting/ boiling, the temperature of the substance remains constant, until it is completely melted/ boiled off).