Science: Technoquest

Juicy vitamins/ Killer paint/ Bigger snakes/ Apple pips

Questions for this column can be submitted by email to sci.net@campus.bt.com

Q How much vitamin C is found in pure orange juice?

A litre of orange juice contains about 300 milligrams of vitamin C, which is five times the recommended daily dose for adults.

Q In the film Goldfinger, one of the women was painted in a non-porous paint which killed her. Would this really happen?

Yes, for several reasons. Firstly, the skin is important for temperature regulation. We sweat constantly: it evaporates and removes heat from our bodies. Blood flowing near to the skin also loses heat as it is cooled by contact with the air. Without these two mechanisms, the body would overheat and we would die.

Secondly, the skin can absorb substances applied to it - such as any toxins in a non-porous paint. These might be eliminated by the kidneys, or they might kill you. Thirdly, a non-porous paint would mean that the skin's waterproof surface layer would get waterlogged (like wearing a non-absorbent plaster for a while) and so be liable to infection. It might even start to fall apart.

Q Snakes continue to grow, although very slowly, throughout their lives. Did this also apply to dinosaurs?

Continual growth occurs in many reptiles, but is particularly noticeable in larger species of chelonians (turtles, tortoises) and crocodilians (crocodiles, alligators and gharials) as well as large lizards (such as monitor lizards). It is one reason why it is so difficult to be certain about the record sizes achieved by these creatures. Microscopic studies on bone from a wide range of dinosaurs indicate that it was probably universal among that group too.

Q Are apple pips poisonous? If so, how dangerous are they?

Apple pips actually contain cyanide, and you can be poisoned by them if you eat too many - though it would take about a cupful. You might be sick of apples by then.

Q Why do moths fly towards light?

Because they think it's the moon. Moths are used to navigating by the light of the moon - they fly keeping the moon on one side. When a bright, artificial light is present, they try to do the same thing but to keep it in a fixed position they end up flying round in circles. The brightness of the light disorientates them and their orbits get smaller and smaller until eventually they hit the light.

Q Where does the word "atom" come from, and who first thought of it?

The word atom comes from the Greek for "not cut". The first person to think that atoms existed - that is, that everything was made up of combinations of some indivisible objects - was a man called Democritus who lived in Greece in 400 BC. He thought that atoms were the smallest things that could exist, and this was generally believed until the early part of this century.

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