A recent episode of Radio 4’s In Our Time focussed on the water molecule, and it was a real eye-opener for me. Because we’re surrounded by so much water all the time, not to mention being mostly made up of it ourselves, we tend to think of it as a very basic, ordinary thing. But the truth is that water is an exceptional substance!
There are a number of different properties of water that are examined in the programme – the phenomenon of surface tension, the different kinds of ice that exist, the fact that water ice floats on top of water (it turns out that this doesn’t happen with any other kinds of ice), and water’s comparatively high boiling point. Again, the idea of something boiling at 100 degrees seems quite commonplace to most of us – yet almost every other liquid on the planet boils at a much lower temperature.
This last fact is linked to another of water’s unique – and useful – properties: the amount of energy that can be stored in it, and released at a later time. It is this property that makes water such a good thing to use when heating our homes. Unfortunately, most of the water that’s available for the purpose has high levels of calcium and magnesium in it (bonded to it in fascinating ways also discussed in the programme) and these give rise to the hard water problems that our water softeners are designed to alleviate.
All in all this was a fascinating programme, which I’d recommend to anyone with an interest in water. It’s free to download from the BBC website.