Explained: Why your own snoring usually doesn’t wake you up

The world is a complex and bewildering place. Now the experts at New Scientist magazine have published a book that answers some of the oddest but most entertaining questions they’ve been asked.

Why does your own snoring usually not wake you up?

You snore most loudly when deeply asleep and hardest to arouse. Also, we live in bodies so noisy that we are equipped to ignore our own noises (such as breathing). This sound cancellation enables us to sleep through our own snores. However, sometimes a violent grunt can break the rhythm of our snoring and our ‘cancellation software’ cannot neutralise it. Then we wake up.

Is it safe to be close to a microwave that’s on?

We can see food cooking inside a microwave oven through the metal mesh incorporated into the glass of the door. This is because visible light has a wavelength of around 500 nanometres — 5,000 times smaller than the holes in the mesh — and so passes through. But the microwave radiation in ovens has a wavelength of around 12cm, roughly 60 times the size of the holes in the mesh, so it’s impenetrable. So unless there is a manufacturing fault or damage to the oven, it’s probably safe enough for you to stick your nose right up against the glass.

Why does my nose run in cold weather?

This is caused by condensation and evaporation. When warm and moist exhaled air passes over the surface of nasal mucus that has been cooled by inhaled cold air, it condenses, just as it does if you breathe out on to a cold mirror. The nasal mucus cannot absorb all the moisture, so the nose runs to get rid of the excess. The liquid running out of the nose is clear and clean condensed water, and is not a sign of an infection. To avoid it: breathe in through your nose and out through your mouth.

Why do my legs wobble standing on a cliff top?

Standing on a cliff where there is no level ground in front of you to offer visual clues to help you avoid toppling, your legs keep over-correcting.

That feels very insecure, which can make your knees shake. Plus, the impulse for legs to tremble when one is frightened seems a primitive one: small children commonly throw themselves to the ground when they’re afraid, in a state of helpless submission. Shaky legs might be part of that response.

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