What are the dietary requirements of a sumo wrestler?

A Rikishi, as a sumo wrestler is called in Japan, eats around 21,000 kilojoules a day, more than double that in the average adult diet. But Rikishi don't eat breakfast. At noon, after training for five hours, they eat their first and biggest meal of the day, a one- pot stew called Chakonabe. This staple of the rikishi's diet contains a mix of vegetables with meat or seafood, and an assrtment of side dishes such as fried chicken, steak, eggs and rice. Dinner is a less structured affair. Wrestlers in the top Makuuchi division weigh, on average, more than 150 kilos, while the average rikishi has 26 per cent body fat.

Why do shower curtains suck in and stick to us?

Falling water from the shower head forces air down and round the shower, creating a horizontal mini- tornado with low pressure at its center, explains David Schmidt, an engineer at the University of Massachusetts, who resorted to detailed computer modelling to solve this riddle. The air outside the shower remains at normal pressure so the curtain is forced inwards.

Is it possible to lie under hypnosis?

Being hypnotised is similar to being moderately drunk," says Dr. Phillip Jones, a psychologist who uses hypnosis as part of his work. "You tend to be more honest and your inhibitions are lowered, but you can control what you say and do to some extent. If you're asked a difficult question you'd rather not to answer, you can lie or snap out of trance altogether." Even if we don't set out to decieve while hypnotised, recollections of our past (or past lives) can be just as unreliable as under normal circumstances, adds jones. For example, courts in Britain give statements made under hypnosis no more credence that other oral evidence.

Do goldfish really have a ten-second memory?

We know goldfish can recognise their owners or keepers," says london Aquarium aquarist Luke Rosser, 'beacause they'll swim to the surface expecting food when the owner approaches the tank. They also get disoriented if you rearrange the objects or plants around them." Research at the university of Utrecht in Holland supports Rosser's view, finding that carp - close relatives of the goldfish - will avoid a particular bait, once caught with it, for a year or more.

Why do we get an itch?

Itching occurs when nerve endings in the skin are distured, says consultant dermatologist David Gawkrodger of Royal Hallamshire Hospital in Sheffield, England. The cause is usually dryness in the epidermis, but it can be something serious, such as liver or kidney disease, which causes substances that irritate.

If baby shampoo contains a "no more tears" formula, why do manufacturers put a "tears" formula in adult shampoo?

It's not so much what we put in our shampoo that makes it kinder on eyes," explains Johnson and Johnson's Brian Walmsley, "it's what we leave out. "Adult Shampoos contain stronger detergents, but in larger quantities. This is because adult hair is thicker, and so dirtier, than a baby's. "Grown-ups also want colourants and conditioners in their shampoos- like silicon. This coats the hair so it feels soft, but is impossible to manufacture in such a way that it doesn't sting your eyes."

What is the point of the small hole in the side of a ballpoint pen?

It helps the ink flow from pen to paper properly. When ink comes out of the plastic tube inside a pen and on to the page, it sucks air with it, creating a vacuum. Outside are will try to flood into the pen to fill this vacuum and if the pen to fill this vacuum and if the pen has only one hole (i.e. the ballpoint nib) this will make the flow of the ink inconsistent as both inrushing air and ink try to squeeze through the same gap. But if the pen has a second hole, the air can flood in through this route without disturbing the ink.