What How Why

It takes the Earth 365 days and six hours to orbit around the Sun. The Six extra hours cannot be counted on the calander. So, to keep an accurate count, an extra day is added at the end of february every four years.

What How Why

When the magma cools, the material which it contains solidifies in the form of crystals. Precious stones are crystals with particular characteristics of colour, hardness and the way they can reflect the light. They are used in making jewellery.

What How Why

To measure the height of mountain, the surface of the sea is taken as the point of reference. The height of the mountain is the distance between the top of the mountain and the surface of the sea.

What How Why

An electric current is a passage of electrons from one electrified body to another which is less charged. When too many electrons are generated, they can move.

What How Why

Rust forms on the surface of iron objects when they are exposed to the air. It is the product of a chemical reaction called oxidization. The more the object is exposed to the air, the more rapidly rust spreads.

What How Why

A Greyhound can run at a speed of 64km per hour, a Weimaraner , once used for hunting wolves and wild boar, can reach speed of up to 56 km per hour in a chase. Many breeds of dog which were once bred for hunting are now more common as pets than hunting Dogs.