Who were the first sea- going sailors and what were early ships used for ? Norse sailors, commonly known as the Vikings, became the first true sea- going adventurers, when they set out in their longships from the firods of Seandinavia and Denmark and began their invasions of England about AD 800. It is known that they crossed the Atlantic Ocean in their open boats to North America about AD 1000-500...

How did man learn to sail? Before man learned to sail he had to discover the principle of flotation and   this is probably did by accident. Noticing how fallen pieces of trees floated in rivers and lakes, primitive man experimented by holding onto logs and discovered that they could support his weight and remain afloat. He developed this ‘floating vehicle’ by tying logs of wood together with vines, bundling reeds together,...

What is the Solar System?   The solar system consists of the Sun and the family of objects that travel round it and accompany it through space. The Sun is a very ordinary star, as far as we can tell, and it is a fantastically hot, luminous globe of gas. Most of the gas is hydrogen. There are nine known planets in the solar system. A planet is a solid body...

What is a Light Year?     a light year is the unit which is used to measure the distance between astronomical objects. It is the distance traveled by a ray of light in one year, and since light travels at a speed of 300,000 km (186,000 miles) per second, this amounts to nearly ten million million kilometers ( six million million miles)! Even so, the nearest star to the Sun...

What is a Galaxy? A galaxy is a huge system of stars, gas and dust which is held together by its own gravity. Our Sun is a small star among an estimated 100,000 million others which make there are thousands of millions of galaxies in the Universe, of all different shapes and sizes, separated by vast regions of space. The Andromeda galaxy is the nearest galaxy to our own and it...

How can a snake eat a pig?   Unlike many other animals, snake cannot chew their food before they swallow it, and so anything they eat must be swallowed whole. But how does a snake manage to eat some- thing as big as, say, a pig? Surely it’s mouth is much too small? Although a snake does have a small mouth, its jaws are not connected together like those of many...