Science: Technoquest

Q Do animals get addicted to substances?

Yes. It seems animals, like humans, can get addicted to substances that are of no biological value. Rats, trained to inject themselves with cocaine, continue to do so even after they start having extreme reactions like seizures. We cannot assume that rats become addicted for the same reasons as humans, or by the same mechanisms, although similarities in brain structure suggest common "addictive" pathways.

A good example of a useful addiction in nature is the koala bear's love of eucalyptus leaves. Koalas will die without them. This addiction is acquired, rather than chosen, as the koala cub gets used to the eucalyptus in its mother's milk. But there are also benefits. Eucalyptus leaves contain precious water. They also contain aromatic oils which help to keep the bears' fur free of parasites, relax their muscles and lower their blood pressure. Other animals eat plants, fruits and berries (for example, opium poppies and rotting fruits) which contain intoxicating substances.

Q Why is it so difficult to iron out a crease when it's so easy to make a crease?

The Home Laundering Consultative Council saysit's all to do with the direction in which the fabric fibres are lying. The fibres prefer to be in straight lines and when you iron in a crease you align them in that way. It is quite easy to get the fibres to do what you want because they want to do it too!

However, because this is their preferred position, it is not easy to iron out a crease once it's there. This involves making all the fibres jiggle up again. The best way to get rid of creases is to dampen the fabric so that the fibres relax and thus become easier to realign.

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