Why does the chameleon change colours? Animals use the technique of camouflage to escape predators. By changing colours the chameleon is camouflaging itself. This is made possible thanks to special red, black and yellow cells in its skin. The chameleon changes colours by changing the...
How do telephones work? Telephones work by sending and receiving electrical signals which represent sounds. When we dial a number a signal passes to another telephone which makes it ring. When the telephone is picked up, a connection is made and people can talk to...
What is the difference between toadstools and mushrooms? There are no differences between the two. In scientific terms there is nothing called a toadstool. Some people call poisonous mushrooms toadstools. But botanists do not use the term. Mushrooms are actually fungi. Poisonous mushrooms contain a...
What is smelting? Iron ore is a rock that contains iron and oxygen. Smelting is the process of extracting iron from iron ore. Iron ore, limestone and coke (a form of carbon) are heated together in a blast furnace while hot air is blasted in....
What is an X-ray? We take X-rays usually after we have an accident or a bad fall. It is a kind of camera that takes pictures of our internal organs. It emits invisible light rays which pass through our skin and muscles but not hard...
Why is there frost more often on clear nights than on cloudy ones? Frost forms overnight when the temperature falls below 0°C and the dew freezes. Clouds prevent the heat that has built up in the land, sea and air during the day from escaping....
How was alcohol discovered? Alcohol is an organic compound. It is a compound of carbon, hydrogen and oxygen. Grapes have natural yeast on their skins. Under warm conditions, grape juice can ferment without the addition of more yeast. This fermented grape juice had a strong...
Why do birds moult? A Birds grow new feathers in place of old ones. The process is called moulting. In the winter season, they grow a thick coat of feathers which keep them warm. During the summer these feathers fall off and new, colourful ones...
Who were gladiators? The Romans loved violent sport. They had amphitheatres to watch violent shows called ‘games’. Gladiators fought each other to the death in these amphitheatres. Sometimes they fought lions with spears, burning torches, or their bare hands.
Where did wealthy Romans live? Wealthy Romans often had two homes. One was a country home or villa and the other a town home. There was a courtyard around which houses were built and had many rooms. They also had running water, kitchens, central heating...
