Were there dinosaurs which lived under water? There were no dinosaurs which lived under water. Initially it was believed that Brachiosaurus was too big to live on land. But the fact is that the pressure of the water would have crushed its ribs making it...
When did man begin eating eggs? Since prehistoric times men have been eating hen’s eggs. The Chinese were familiar with chickens 3,500 years ago. But they probably reached the western hemisphere only with the second voyage of Columbus in 1493. Today the chicken is the...
What gives us our appetite? Humans experience hunger, thirst and appetite. The hunger centre in the brain regulates the activity of the stomach and intestines. Hunger is a signal that the body needs nutrition. This activates the stomach and intestines making the stomach rumble. But...
How is rope made? Rope has always been needed for making rigging of ships, tying bundles and hauling things. So rope making is quite an old industry. The Egyptians used vegetable fibres to make rope. We follow the same method today. Fibre used to make...
How does a sundial tell time? For man, the sun was his first clock. By watching its movements as it made its way across the sky, he could guess the time. The sundial is a shadow clock for it helped to tell time by observing...
What is cryptography? Cryptography is the art of writing using a secret code. Nowadays governments and businesses use codes to communicate important and confidential messages. One can create codes by substituting a number, letter or other symbol for each letter in a message. Another method...
When can one see three suns? When there are thin clouds high in the sky it is possible to see three suns. The clouds are formed from bits of ice. These ice bits bend the light coming from the sun. This makes it seem as...
Why do comets have tails? As a comet approaches the sun it becomes warm and its icy surface melts, becoming gas. The gas forms a cloud when it mixes with dust. The cloud shines in sunlight and becomes visible. As the comet approaches the sun,...
Why does cork float? Cork is lighter than water. The walls of the cells in cork are filled with air. Water cannot easily penetrate these cells. So the cork does not become waterlogged which would make it sink. Cork is the outer bark of the...
How are sand dunes formed? Sand dunes are formed when the sand that is carried by the wind encounters an obstacle and piles up. The dunes are formed by trillions of sand grains. As they are constantly pushed by strong winds they don’t remain in...
