What is Motion? How astronomers came to understand the structure of the solar system. They arrived at their conclusions by observing the planets and measuring their distances from the Earth and the speed of their orbits. Their findings were not completely accurate because these astronomers did not understand the laws of motion. In fact, these were not fully under-stood until this century, when Einstein, continuing the work of Isaac Newton, formulated...

Why is Johann Kepler so important? Tycho Brahe first heard of Kepler when he read his book Mystery of the Universe, published in 1596. This supported Copernicus’s theory that the Sun was the centre of the Universe and tried to show how the distances of the planets could be worked out. Brahe was so impressed that he employed him to study the movements the planet Mars and so prove Brahe’s theory...

Who was Tycho Brahe? Tycho Brahe (1546-1601) was a brilliant Danish astronomer. King Frederick II of Denmark was so impressed with his skilled observations of the stars and planets that he gave him an island called Hven, near Copenhagen where Brahe built an observatory. Unfortunately, Tycho Brahe was reputed to have a most unpleasant character, and was much disliked by the inhabitants of the is-land. It is said that he lost...

Why is Indian music never played by orchestras?   Indian music is played by small groups of musicians. Often there is just a solo instrument and a small drum. The players like to make up the music as they play. If there were many more musicians, the music would have to be written down and the players would not be free to play as they like. For this reason, large orchestras...

What do folk dances mean? Nowadays, we enjoy folk dances as entertainment but many dances once had special meanings. Some dances originated as imitations of animals or of simple kinds of work such as wood-cutting or gathering the harvest,  to mark the passing of the seasons and to please the gods. Other dances reflect times of war or commemorate warriors’ deeds. Sword dances were originally war dances. In the East, dances...

Which instruments are in a symphony orchestra? A symphony orchestra may contain over a hundred instruments, but they are not all different from one another. In fact, there are only four major groups of instruments: the strings, woodwind, brass and percussion. The group to which a particular instrument belongs depends on the way it is played. String instruments have a wooden body and four strings, and they are played by stroking...

What causes sonic boom? Nowadays, most people have heard the bang caused by an aircraft travelling at the speed of sound, but do you know why it occurs ? Sound is caused by a disturbance which creates waves that emanate from the centre of the disturbance. These waves are sound waves. When these vibrations are picked up by the ear drum they are interpreted by the brain as noise. When someone...