Warming things up

Warming things up is an everyday occurrence

You pop a muffin in the microwave. You wrap your cold hands around a steaming mug of soup.

In each case three things happen:

• The temperature of the warmed object rises.
• The associated thermal store of energy fills a little.
• More energy is shared amongst the particles in the object being warmed, and they move around more.

All of these three aspects of warming up are linked and all happen together.

Warming in different ways

In two examples, the warming takes place in two different ways:

• By radiation (muffin in microwave) – the heating by radiation pathway.
• By conduction (cup warming hands, radiator warming socks) – the heating by particles pathway.

The last two need particles as a physical (particulate) link between the things doing the warming (the cup and the radiator) and the objects being warmed (the hands and the socks). Here the pathway from one store to another is warming by particles (see episode 03).

As the energy from the first thermal store (associated with the warm object) is shifted to the second thermal store, associated with the cooler object, one store is emptied and the other is filled. In the first example the muffin is warmed when electromagnetic radiation arrives, and this is an example of the warming by radiation pathway in action (see episode 03).