We hear a lot about ‘test-tube’ babies. These babies are not, in fact, born in a test-tube, but they do begin life in one. Medicine can sometimes help people who cannot have children. Normally, a new life begins in the mother’s womb when a sperm cell from the father fertilizes an egg cell from the mother. The two cells fuse …
Read More »Can a scorpion kill a man?
Scorpion are particularly ferocious animals, even to each other, and so they lead solitary lives. They live in dry warm, areas of the world and in the wild hide themselves away in dark places, under logs or stones, for example, waiting for their prey. This normally consists of small insects and spiders. As scorpion cannot see very well they rely …
Read More »At what speed does electricity travel compared to light?
Electrical fields in theory do transmit at the speed of light. In real systems, wires have capacitance and other effects that slow the propagation. Typical propagation speeds are 0.3 to 0.7 times the speed of light, depending mostly on the wire shape and size, characteristics of wire insulation, and interactions with other conductors.
Read More »Are there people on Mars?
Percival Lowell, an American astronomer, thought he saw canals criss-crossing the deserts of Mars, when he observed the planet though his telescope early this century. He believed that these canals were built by a Martian civilization to bring water for irrigation from the planet’s polar caps. However, space probes have shown that the canals were simply optical illusions, and that …
Read More »Are bats really blind?
Bats are not blind. Like many animals, they are born blind, but gain eyesight from the time they are seven to nine days old. Bats are night creatures. They come out only at night to hunt. Although they can see reasonably well they have no special eyesight possessed by other night creatures like the cats and owls. Instead, bats fly …
Read More »Are all snakes dangerous?
It depends what you mean by dangerous! Certainly, not all snakes are poisonous, and of those which are, only a very small number are dangerous to people. But in the same way that people could be said to be a danger to the things they eat, snakes are dangerous to their prey. Most snakes kill their prey- rats, mice and …
Read More »Are all deserts hot?
The definition of a deserts is a place where the lack of moisture makes it impossible for anything but a few special life forms to grow. This applies not only to hot places, like the Sahara and the Gobi deserts, but also to very cold places too. Because all or most of the moisture there is turned to ice, almost …
Read More »Anyone for the shuttle?
When the first manned satellites went into space in the early 1960s, many people felt that the wildest dreams of science fiction writers were coming true. It was only about 50 years earlier that the first aeroplanes had flown. What amazing progress had been made in half a century! But in the next 20 years events moved still faster In …
Read More »Amazing facts about animals
Amazing facts about animals — A captive, great brown bear of Alaska, a close relative of the fabled grizzly bear, weigh about 650 kilograms! The female Emperor penguin comes to the land, lays one egg on bare ice, then immediately returns to the ocean. The male keeps the egg warm for two months until it hatches, by rolling it onto …
Read More »Accidental discovery
During World War I a metallurgist called Harry Brearley tried mixing chromium with steel to make a stranger gun barrel. It didn’t work. The barrel shattered. But the metal pieces he threw away outside stayed bright and didn’t rust. Quite by accident, the secret of making stainless steel had been discovered.
Read More »