How does a thermostat work? A thermostat consists of a strip made of two metals which is connected to an electrical circuit. When the strip warms up, the molecules in the upper metal vibrate more than those in the lower one. The upper metal expands...
Why does water have a wrinkling effect on the skin? The skin on our hands and feet have a protective coating or layer of protein called keratin. The keratin on our finger tips and toes is more loose than it is elsewhere. When we are...
When did dinosaurs die? Dinosaurs became extinct about 65 million years ago. In some places they vanished slowly and in others they disappeared suddenly. Many theories have been put forward to explain their death. One is that a meteorite struck earth. Another is that mammals...
Who were the first doctors in the world? The earliest doctors plied their craft in ancient Egypt and Chin Egyptian physicians used drugs and potions to treat patients. Injuries were treated by surgeons while ‘evil spirits’ were exorcised by priests. Imhotep, an Egyptian, was the...
Which animal did the Mayans worship? The Mayans worshiped the jaguar. Mayan warriors used to wear jaguar skins and head dresses. Their belief was that wearing them would make them brave and fierce like the jaguar when they were doing battle. The Mayans also worshiped...
Why do people eat? People eat to stay alive, find energy to do their tasks, and to grow. Without food our body will not be able to function properly. We need to eat proteins for growth, and carbohydrates and fats for energy. We also need...
Why is Io called the ‘pizza moon’? Io is one of Jupiter’s moons. It is a very colourful moon and this has earned it the name, ‘pizza moon’. It is also rather unusual as it has active volcanoes on it. These pour out liquid sulphur...
How is synthetic rubber made? Natural rubber is made from latex which is a white fluid of the rubber tree. Synthetic rubber is made using man-made latex which is a combination of chemicals. Its main ingredients are butadiene and styrene. Butadiene is a gas while...
How is whiskey made? Whiskey is an alcoholic beverage which is distilled. Beer and wine are not distilled. In distillation, different kinds of liquids are separated by boiling them. Whiskey is made by mixing malt to a cooked mash of grain mixed with water. The...
What is leather? Leather is the hide or skin of animals that has been tanned. Tanning makes the hides and skins soft and flexible. The hides are ‘cured’ or preserved before tanning. For this the skins are salted. After tanning, waxes, resins, shellac, etc. are...
