What causes high tides? Tides are caused by gravity. The earth exerts a pull on the moon and likewise, the moon exerts a pull on the earth too but with less force. This pull of the moon causes the ocean water nearest to it to...
Which dinosaurs had the heaviest bones? The biggest and heaviest bones were found in the sauropod dinosaurs. A thigh bone which was found weighed 450 kg. In the early days it was a big task to transport the bones. But now helicopters have come to...
What is amber? Amber, a brittle yellow and translucent substance was formed from a resinous material produced by pine trees many years ago. The substance accumulated on the ground. Later it was buried under the ground or water. After millions of years, it became fossilized...
What is a volcano? Volcanoes often resemble mountains. They are cracks in the earth which go from the surface right down to the hot, melted rocks below. The rocks are known as magma. The volcano erupts when the boiling magma rises up through the crack...
What are viruses? Viruses are organisms that cause disease. They are visible only under electron microscopes. Opinion differs as to the exact nature of viruses. Some scientists believe that they are similar to genes while others think that they are somewhere between living and non-living...
Which are the poisonous spiders? Not many spiders are poisonous to man. Spiders usually use their poison only to defend themselves. One of the more dangerous spiders is the black widow. Its bite can cause severe pain and illness. It has a red, hour-glass shaped...
What is immunity? Immunity is the ability of the body to resist and fight infections caused by disease causing germs and pathogens. The body produces antitoxins to battle the toxins produced by germs. Acquired immunity is when the body acquires resistance to a disease after...
What are catacombs? Catacombs were underground tombs near Rome. Here was where the bodies of the early Christians who were persecuted by the Romans were buried. The tombs were cut in soft rock in a sacred area surrounding Rome. When emperor Nero began to persecute...
How do we taste food? The human tongue is covered with tiny, wartlike bumps called papillae. The walls of the papillae contain taste buds which are distributed in various zones which correspond to different tastes like bitter, sweet, sour and salty. Smell is also part...
Who discovered the light year? Danish astronomer, Olaus Roemer discovered the light year in 1676. Light travels a distance of 5, 880,000,000 miles in a year. This is called a light year. Light travels at a speed of 186, 284 miles per second. Light year...
