Diana Craig

But it wasn’t until the appearance of primitive bacteria, millions of years ago, that the vital component of the air we breathe first materialized.
Using the power of the sun in a chemical process called photosynthesis, these bacteria absorbed carbon dioxide from the atmosphere and gave off a new gas: oxygen.

To compensate and reduce stress on the plane’s fuselage, the pressure inside the cabin is lowered.

It contains the highest density of air, holding about half of the planet’s atmospheric gases.

YOU MAY NOT be able to see everything that’s going on in the atmosphere, but there’s never a dull moment up there.

Here’s (a bit of) the science behind it all.

So if the forecast includes the words ‘high pressure’ you should be in luck because the weather is likely to be fine, clear and dry.

This explains why gliding birds usually only take to the skies in sunny weather, and why they generally become active only after ten o’clock in the morning, when the thermals have become strong enough to give them the necessary lift.

If one front follows another in fairly rapid succession, this can lead to changeable weather – as often happens in winter in Britain, for example, which is notorious for its unpredictable climate.

‘If you don’t like the weather in Buffalo, just wait five minutes.’

Winds generally follow the isobars (lines joining points of the same pressure). When the isobars on a weather chart are close together, it means that there is a steep change in pressure – so you can expect a blustery day. Close isobars plus low pressure mean it’s going to be wet too.