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Q Can dangling a silver spoon into an open bottle of champagne stop it going flat?

A Despite rigorous assurances by people in the wine industry that this phenomenon does work, scientific analysis suggests the contrary. If champagne is kept cool, once opened it will stay fizzy for 24 hours or so because carbon dioxide (the fizz) is more soluble in a mixture of alcohol and water, such as champagne, than in sugar and water-based soft drinks, which tend to go flat more quickly. So with or without the silver spoon, champagne will hold its fizz. But, as the Champagne Bureau points out, there is only one sure way of preventing champagne from degassing and that is "to drink every last drop".

Q Why don't Christmas trees lose their leaves in the winter?

A Christmas trees, like other conifers, have specially modified leaves, which means they do not need to shed them in the winter. A tree uses its leaves not only for collecting light but also to exchange gases such as CO2 and water vapour. Deciduous trees shed their leaves in winter to slow down their water loss. Conifers, in contrast, can keep their leaves because they are designed to retain water. They have a much smaller surface area and are coated in a thick, waxy skin which stops water from evaporating. With these features they can keep their leaves all year - though they have not yet adapted to having their roots cut off and being shoved in a bucket and put indoors. So by the time it is disposed of on Twelfth Night, even the hardy conifer will be shedding its leaves.

Q What causes a hangover?

A Normally, the body produces a chemical called anti-diuretic hormone (ADH), which stops you going to the toilet too frequently. Alcohol stops the ADH being produced, so you go to the toilet more often and rapidly become dehydrated. It is this dehydration that can bring on at least one symptom of a hangover: the headache. But it is not the alcohol that causes the worst symptoms of a hangover. If you really want to feel bad, drink cheap brandy and red wine. The colourings and the tannin from the wooden barrels in which they were matured all add to the cocktail of chemicals you are poisoning yourself with. The resulting hangover is a symptom of the poisoning.

Q How high up do satellites orbit Earth?

A The minimum orbit for any satellite is about 150 kilometres, although some military satellites orbit at 50 kilometres. At this height these little mechanical spies often do not last more than a few weeks before they enter the Earth's atmosphere and burn up. Satellites used for communications and meteorology are found much higher, at 36,000 kilometres, in a geostationary orbit. At this distance from the Earth they orbit at the same rate as the Earth rotates - staying above the same place on the Earth's surface. Navigation satellites orbit at about 15,000 kilometres, while polar and Earth observation satellites orbit at only 500 kilometres.

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