## Summer’s gone

Yesterday’s 15 mls of rain was very welcome but I’m not so keen on the change of temperature that’s come in its wake.

We’d been enjoying temperatures approaching 30ish for nearly a fortnight.

Today unless the chill wind drops and the clouds disappear we’ll be lucky to get to half that.

### 3 Responses to Summer’s gone

1. Andrei says:

Today unless the chill wind drops and the clouds disappear we’ll be lucky to get to half that.

The temperature where you are is below -126.575 C° Ele?

Not even Siberia gets that cold.

If you’ll excuse my pedantry

2. homepaddock says:

Please explain your calculation – I thought half of 30ish was 15ish.

3. Andrei says:

Thermodynamics Ele

The Celcius scale for measuring temperature is defined by arbitarily setting the zero at the freezing point of water and the 100° at its boiling point. It provides a convenient range and scale for everyday use but is arbitary.

To see this – your 30C° is 86F° half of which is 43F° which is 6.1C° somewhat different from your 15C° (assuming I have done my arithemetic correctly.

So talking about a temperature being “half” of another temperature and ambiguous at best if not meaningless

Unless

we relate it to something else – Energy perhaps

And very loosely temperature is a proxy for the amount of energy contained within a fixed volume and thus if the temperature is halved the amount of energy within that fixed volume is halved

On the Celcius scale the point where the energy has dropped to zero is −273.15C° which is 0K° or 0 Kelvin or absolute zero

And using the Kelvin or Absolute scale we can talk about dividing the temerature by two or any other number in a meaningful and unambiguous way

This 30C° is 303.15K° which divided by 2 becomes 151.575K° = 121.56C° (no surprise I messed up the arithmetic is my original comment – when being pedantic you are just asking to be tripped up on details which is a jolly good thing, a kind of karma )