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Curly sausages, earworms and runny noses - here's the answer; Want to know the answer to some of life's mysteries? Sion Morgan has been finding out thanks to a new book...

EVER wondered why your nose runs in winter? Why you used to hate olives but now can't get enough of them? Why you can't get that song from Frozen out of your head? Well wonder no more. Boffins at New Scientist magazine have collected some of the world's strangest questions and attempted to answer them in a newly-released book.

Question Everything is the latest volume of answers to questions posed by the magazine's readers.

Editor Mick O'Hare said: "It's our stock-in-trade: finding out how and why the things surrounding our everyday lives do what they do.

"This time we set out to make people think a little more about our universe and what's in it and the physics, chemistry and biology that keep it all on the move."

Here are some of the questions - and the answers...

If the sun is a star just like all the others why does it appear yellow rather than white? There are two main reasons why stars appear white, even though they really cover a wide range of colours from deep red (cool stars, less than 3,000degC) to bluish-violet (hot stars, greater than 30,000degC).

First, the human eye is poor at detecting colours at low light levels. Hence, most stars, especially the fainter ones, appear white.

Secondly, many of the stars visible to the naked eye are genuinely white or bluish-white, being among the hottest and most luminous ones in our region of the galaxy, such as Rigel in Orion.

Other stars of the same temperature (about 5,500degC) and size as the sun, or even cooler and smaller ones, are either too dim for their colour to be distinguished by the naked eye or cannot be seen at all without a telescope.

What allows fruit cake to survive so long? It's the sugar content. Sugars are hygroscopic - that is, they draw water from their surroundings, including from any bacteria or fungi.

This prevents growth of such microbial contaminants.

Bees process honey for exactly the same purpose, reducing the water content of the collected nectar to around 20% so that the honey, which is 80% sugar, can resist microbial spoilage.

Traditional fruit cake can be around 60% carbohydrate, with the dried fruit and sugar together contributing about three-quarters of that. In other words, fruit cake can be as much as 50% sugar.

How can flies fly at speed into a pane of glass and seemingly remain uninjured? The anatomy of flies is springy but the main reasons they survive are matters of scale.

Although flies fly at huge speeds relative to their size their actual air speed seldom attains three metres per second and is usually nearer one metre per second.

Given that kinetic energy is 0.5 multiplied by mass multiplied by velocity-squared, the amount of energy per milligram of fly is tiny.

In hitting a glass pane it will barely bend its own bouncy bristles.

Hitting a moving sheet of glass is a different matter.

At modest highway speeds a car windscreen travels more than 30 times faster than a dawdling fly.

The resulting squared velocity inserted into the equation above means that the imparted energy is perhaps 1,000 times as great.

Why do blue whales need to be so big when they only eat plankton? Blue whales need to be so big precisely because they eat tiny food - specifically krill, small crustaceans that feed on plankton. Krill defend themselves against smaller predators by forming very dense shoals that confuse attackers. Blue whales get around this by swimming very fast at the shoal with their mouth wide open, often from below, and engulfing as much as they can.

Their pleated throat can expand enormously to take in as much of a shoal as possible.

The whales then strain the krill by forcing the water out through the baleen plates in their mouth.

Because each attack uses up a lot of energy, this feeding strategy - called lunge feeding - only works if the animal can take in enough krill to more than repay the cost, so the whale needs to be huge to use it effectively.

Why does my nose run in cold weather? This is caused by condensation and evaporation.

In cold air there is not much water vapour but warm exhaled air is almost completely saturated with water vapour from its passage over the warm surfaces of the lungs and airways.

When the exhaled warm and moisturised air passes over the surface of the nasal mucosa that has been cooled by the cold air on its way into the lungs, it condenses, just as it does if you blow exhaled air towards the colder surface of a window pane or a mirror.

As the nasal mucosa cannot take up all the moisture that condenses on it, the nose runs to get rid of the excess.

The water running out of the nose is clear and clean condensed water and is not a sign of an infection.

Why do we sometimes get a tune stuck in our heads and play it over and over again even though it's driving us crazy? Getting a song stuck in your head is known by many different names including stuck song syndrome, or earworm, a term translated from the German word Ohrwurm.

It has been suggested that it has an evolutionary origin. Before writing was invented, just 5,000 years ago, songs helped people to remember and share information.

Earworms occur when you subconsciously detect something unusual about a piece of music.

Usually between 15 and 30 seconds long, an earworm is replayed in your mind in a loop and is difficult to dislodge.

Why do we grow to love tastes that we disliked when we were younger, like olives or wine? As we age we progressively lose parts of our senses of taste and smell. The first parts to go are those that make us dislike certain foods.

Much later in life we begin to lose the parts that allow us to enjoy our favourite foods. In between is the golden age of the gourmet.

Birds sing at dawn and tend to go quiet after dusk. So in summer do they get enough sleep? Birds do sleep mainly at night but only in very short snatches.

They will also sleep during the day provided they feel secure enough, so the length of daylight makes very little difference to them.

They sing for several reasons, including to attract a mate and to keep in touch with the flock. But the principal reason is territorial.

We hear them mostly at dawn because it is quiet and therefore the best opportunity to re-establish territories.

Most sing during the day, too, but this tends to be drowned out by a cacophony of traffic, music and the ubiquitous power tool.

Why does beer come in brown bottles? Nearly all beer contains hops. These provide the bitter taste and also act as a preservative.

Hops contain isohumulones, which provide part of the bitter flavour. When UV light hits these compounds they decompose and this leads to a "skunky" flavour, so called for obvious reasons. To protect against this, manufacturers use brown bottles that block out some of the UV rays.

Why do some sausages curl when they cook? Sausage skin is mostly collagen, which shrinks violently in cooking because it is degraded and dried by the heat.

Most cooking equipment applies heat asymmetrically, causing uneven shrinkage, which creates curl.

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Why do some sausages curl when they are being cooked? <B JON FULLER-ROWELL-BPMSTF
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Publication:Western Mail (Cardiff, Wales)
Date:Nov 13, 2014
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