When did man begin to discover that there were other continents? The Greeks had an astonishing knowledge of the world around them, the advances they made in science and astronomy hold good, even today. But the Romans who came to power after them in 500 BC were really better warriors than they were men of thought. The routes they followed for their invasion of England, begun in 55 BC were, on...

Who drew the first accurate map of the known world? The most knowledgeable map-maker of Ancient Times was undoubtedly Ptolemy. He was a Greek astronomer living in Egypt about 200 years after Christ. He drew the world’s first most accurate map, but before doing this he carried out an enormous amount of research. He collected information from every source available to him. He interviewed Greek sail-ors who had travelled, anywhere at...

When was the first map drawn?   The Egyptians were the first people to have been known to draw maps, which would have been as early as 3000 BC. However, their estimations were very wrong, as they thought Egypt was the centre of the world and this world was surrounded by water. But none of these maps remain, as they we drawn on papyrus, which is a material paper and so...

How many kinds of whale are there? There are many different kinds of whale, but they can be grouped into two sorts : those with teeth and those without. Those without teeth are called baleen whales. Whales such as the blue whale (above), the right whale and the humpback whale are all baleen whales. In-stead of teeth, baleen whales have enormous rows of brushes, called baleen plates, inside their mouths attached...

Are whales fish? Although whales spend all their time in the water, and are shaped rather like fish, they are mammals, however, just like you or I. Fish use their gills to take in oxygen which is dissolved in water, but whales must come to the surface to breathe air, although they can stay under water for nearly an hour. Instead of moving their tails from side-to-side when swimming (as fish...

How fast and powerful are railway locomotives? The fastest steam engine was the British `Mallard’ which reached 203 km (126 miles) per hour. The most powerful were the huge engines built in the USA, such as the ‘Mallet’ locomotive. There are now few steam trains. Instead we use electric and diesel engines. Electric trains pick up current from extra ‘power’ rails or overhead cables. The French TGVs (Train Grand Vitesse, French...

How can trains run underground and climb mountains?   In big cities there is often no room for railway tracks. Trains go either under or over the roads. The ‘tube’ trains in London run as much as 67 m (220 ft) deep. Whole stations are hollowed out under the surface. In New York the subway sometimes runs under-ground and sometimes on stilts over the road. When main railway lines have to...

How does steam work engines? When water is boiling in a kettle steam rushes out of the spout and lid with great force. It often moves the lid up and down as it escapes. This force is what drives steam engines. A fire heats water in a boiler, sending steam to a cylinder. This is a short, strong pipe with a round piston inside, which can move up and down. When...