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...

How do jets jump? The Hawker Siddeley Harrier is a fighter that uses such an ingenious system for vertical and short take-off and landing that it has earned the nickname jump-jet’. Powered by a Rolls-Royce Pegasus engine, it has two compressor/turbine systems. Sixty per cent of the exhaust from the front system is discharged by fans through two front nozzles, one on each side of the aircraft. The remaining exhaust, plus...

What is the world’s most successful commercial airliner? While there are more Boeing 727’s flying in the world’s airline fleets than any other aircraft, most airline executives would say that the Boeing 747 or ‘jumbo jet’ is the world’s most successful airliner. This is because it carries more passengers than any other jet airliner and operates so efficiently. When it carries a full pay-load of passengers, it is the most profitable...

How have jet aircraft made the world seem smaller? The first jet planes were military ones. In 1952, however, the first passenger jet airliner entered service. This was the De Havilland ‘Comet’, built in Britain. Nowadays there are huge ‘jumbo’ jet airliners, like the Boeing 747, each carrying several hundred passengers. These travel at around 800 km (500 miles) per hour. Recently supersonic or faster-than-sound passenger jets have been developed. The...

Who developed the first jet plane? The first successful jet flight was in the German built `Heinkel He 78′ in 1939. It was designed by Ernst Heinkel. Soon afterwards a British jet, based on the work of Frank Whittle, flew. Both sides in the second world war developed jet fighters but the war ended before they were used. Today’s combat aircraft includes the Tornado. Jointly developed by Britain, West Germany and...

How do jet engines work? Propeller engines like those on early planes worked like screws. They gripped the air and pulled the aircraft along.  Jet engines are quite different. They use a very simple but very important fact. If you stand on a sheet of ice and throw something- heavy away from you will find that you slide in the opposite direction as you throw. This ‘reaction’ always happens. Sir Isaac...

Who won the race to the South Pole? It was only fully realised, as late as 1820, that the icy wasteland of the Antarctic Continent was in fact, a mainland. This sparked off an it6exploratory fervour equal to that of the Great Age of Discovery at the end of the fifteenth century. There were as many as 14 major attempts at reaching the South Pole through the hostile and unknown sea...