Ask Mr Brain . . . all will be explained

PUBLISHED : Monday, 04 September, 2000, 12:00am
UPDATED : Monday, 04 September, 2000, 12:00am

What is the biggest living thing on Earth?

The blue whale is the largest animal that ever lived, bigger even than the largest dinosaur! But even the blue whale is dwarfed by the redwood trees and sequoia trees that grow in the United States.

The Redwood trees that grow in California are the world's tallest trees, many reaching 100 metres! The sequoia trees, while not as tall, have much thicker trunks.

One huge sequoia is named after a famous US soldier, General Sherman. The tree is 83 metres high and the base of its trunk is more than 11 metres across, it weighs more than 2,000 tonnes, making it the most massive of all living creatures. It is thought to be about 3,500 years old.

If blood is red, why are veins blue?

Blood is bright red when it leaves the lungs (full of oxygen to deliver around the body). When deoxygenated (goes back into the lungs after passing through the body), blood is dark red.

Veins seem blue because some light that hits skin is absorbed and the rest reflected back to the eye. Since only higher energy wavelengths can do this (lower energy ones are not powerful enough), only higher energy wavelengths are seen - and these are blue.

But did you know that lobsters and horseshoe crabs have blood that is actually blue?

Why do people clink glasses together after a toast?

There are several stories and no one knows exactly which one is true be cause the custom has been around for so long.

One story about clinking glasses is so that each person's wine would spill into others' glasses, to make sure no one is being poisoned (or everybody is).

Another story is that the custom originated in the Middle Ages, when every alcoholic drink was believed to contain actual 'evil spirits' (Some types of alcohol are called spirits). If someone drank that wine, the spirits would stay inside his body and make him do strange things. It was believed that bells and other sounds could drive spirits away, hence the clinking of glasses.