Who invented printing? The Chinese invented block printing around 2,000 years ago. Characters were carved on wooden blocks and covered in ink. Then they were stamped on to paper. Modern printing began in the 1440s. This was done with movable metal type. It was a...
Why is the butterfly born twice? The butterfly has two distinct stages in its life. It comes out of the egg as a caterpillar which feeds on leaves voraciously and becomes plump. The caterpillar then spins a covering around itself which is called a cocoon....
What is a lodestone? A lodestone can be described as a compass of early times. It was used mostly by sailors to help them with navigation while sailing on a ship. It consisted of a piece of magnetite which was a rock containing iron that...
What is inertia? All objects resist change and this is called inertia. Objects find it easier to continue doing what they are doing at a particular time unless strong force is applied to them. Then it may change its position, shape or movement.
Who was responsible for Persia’s greatness? King Darius I was the ruler who made Persia great. He was the ruler from 521 to 486 BC. He built an empire that included Egypt and the Indus valley. Taxes and tributes paid by those he conquered brought...
Which animals were the first to be based in land? Amphibians could live on land but they had to return to the water to breed. So they were not true land animals. The eggs hatched into small tadpoles which had to remain in the water...
How did music originate? Music began when man learned to sing and love songs and dirges or sad songs were the first songs to be sung. When dance developed, a different sort of music originated with man clapping his hands or stamping the earth. One...
What are the common features of living things? Living things have six common features. They can feed and the food is used to produce energy or build or renew body parts. Secondly, they can grow by becoming larger or taking on different forms during their...
What causes a reflex? A reflex is an automatic or involuntary response by the body to an external stimulus. Reflexes are caused when nerve impulses bypass the brain. Instead they are transferred by the spinal cord to motor cells which send currents to the muscles...
Why is Venus called the Evening Star? Among the planets, it is Venus whose orbit comes closest to earth. After sunset, Venus is visible, shining in the western sky. This is why it is called the evening star. In size, Venus is almost the same...
