QandA

Q&A Tabs

Phlegm is the mucous secretion of the respiratory passages. The cilia cells that line these passages are continually driving the phlegm upward to the throat, where it triggers the swallow reflex...

There are two possible explanations why dogs find it hard to hear or recognise your voice over Skype. Firstly, Skype (and voice telephone systems in general) are optimised to transmit frequencies...

Water has a very high volumetric heat capacity. Raising the temperature of a cubic centimetre of water by 1°C takes more than 3200 times as much energy than you’d need to heat the same...

Astronomer Fred Hoyle was the first to point out that if you could drive a car upwards at 95km/h (60mph), it would only take about an hour to get into space. To get to the Moon would take a little...

Until around 100,000 years ago, Europe was dominated by the Neanderthals. But by 28,000 years ago, the last of them had vanished from their final hold-out in Gibraltar, having apparently lost out...

All female mammals have a clitoris, the sole purpose of which is to react to sexual stimulation, and presumably this stimulation has evolved to be pleasurable for most species. But establishing...

To create a sound, we have to set matter - whether it's a gas like air, a liquid or even a solid material - in regular motion, creating a wave of specific frequencies, which we hear as a sound of...

Mirrors don’t reverse left and right either – that’s just our interpretation of what happens. Your reflection in the mirror is actually reversed front to back – if you have...

Discovered by an American student named Gary Flandro in the mid-1960s, the slingshot manoeuvre usually involves spacecraft briefly 'coat-tailing' a planet orbiting the Sun, extracting some of the...

The ice disappears because the wind blows away water molecules that have evaporated or 'sublimed' from the ice, so the ice slowly shrinks in size. The molecules that escape are those with the...

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There are 7 billion humans and around 200 billion birds in the world. That seems like a lot of two-legged animals, but non-human mammals number around 500 billion and almost all of them are four-...

A combination of the words ‘smoke’ and ‘fog’, the term emerged around a century ago to describe the dense, choking mix of gases and soot that was becoming common in big...

It would be very difficult. Insects pollinate at least a third of the total volume of crops cultivated worldwide, and many are useful predators of non-insect pests such as mites. Even if we...

Let us know what you think this is in the comments below. It features in our November issue's Q&A section. The answer will be revealed in the December issue.

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The antibiotic penicillin is made from the fungus Penicillium chrysogenum. Stilton and most other blue cheeses do use Penicillium mould to create the blue veins, but they use a...

Addictive drugs interfere with neurotransmitters, the chemicals that transmit signals around the brain, and their receptors. This causes changes to the brain’s reward system. This can create...

Our evolutionary ancestors lived with lots of toxic plants and we evolved a gene that makes the toxins in these plants taste bitter to discourage us from eating them. Children probably evolved a...

It’s not just humans that enjoy a smooch; lots of animals have courtship behaviours involving the mouth. Pigeons touch beaks, cats and dogs nuzzle each other, male fruit flies lick the...

Yes, if you want to attract women, but only when beards are relatively rare. In Britain big beards are currently popular, but some say we have reached ‘peak beard’ and hairy chins will...

Arachnophobia, or fear of spiders, heads most Top 10 lists, although it’s impossible to be precise about the true order. Happily, most of us can avoid seeing spiders very often, and...

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