An airport is a place where aeroplanes take off and land. It has three main features-it handles the passangers, Mail and freight it makes sure that all aircrafts take off and land saftely and on time and it provides hangers and workshops so that planes can be checked regularly.
The main operating centre of an airport is the air traffic contorl tower, where controllers organize the landing and take off each aircraft. The control tower equipped with computers and raders.
The ground controller guides the piolet of the aircraft from a hight of 6 to 8 km onto a concerte runway about 3km long and 60m wide.
As soon as an aircraft lands, it moves along or taxis to an area called apron.
The trucks are avilable here to carry baggage to the terminal and the fuel tankers move in to refill the air-crafts fuel tanks.
How do airships float in the air?
Airships use lighter-than-air gases to fly. An airship looks like a cigar-shaped bag under which is slung a cabin and engines. The first
sucessful airship made its journy in 1852. It was powered by a steam
engine and could manage a spped of 8km/hr.
During World war I, Airships were used to bomb cities. The Graf Zeppelin air ship of Germany flew around the world in 1929. But airships didnot last very long as they met with a series of disasters.
They were not safe for the passengers because they were filled with
dangerous hydrogen gas. Airships today are used for advertising and filming. They are filled with helium as it is safe and does not catch fire.
How did bicycles originate?
Bicycles are a cheap and easy means to commute. The earliest bicycles were called 'Dandy horses' These were invented in 1700s
and were simply two wheels that were joined by a rod and had a seat on top.
The rider pused it along the ground on foot. Bicycles with pedals appeared in 1865. These were known as bone shakers because the seats had no springs. Then in 1883 came the "Penny farthing" bicycle.
These cycles had a very big front wheel and a small rear wheel. They had soild tyers and a step to help the rider mount. The modern type of bicycles appeared in the 1880s.
They had chaindriven rear wheel and had air-filled tyres.
How did boats orginate?
Boats have been the means of the transport for man since times immemorial. The first boat dates back to prehistoric times. They were simply floating logs or driftwood paddled with hands.
The first real boat appeared later. One was the dug-out-canoe, Which was a log hollowed out by fire or stone tools. Another kind was a raft made of skinsstretched over a light farmework.
Small, Round boats known as coracles and the kayaks built by Eskimos were made by using skins. later wooden boats were made sturdier by adding a keel at the bottom and sails were attached to catch the wind.
The invention and addition of steam engine to the boats added a new dimension to water transport.
What is a bathysphere and a bathyscaphe?
The Bathysphere is a steel sphere with look-out windows and it is lowered in the water by a cable on a ship. The bathyscaphe is an underwater vehicle or an ocean ballon which can move freely.
It has a cockpit for the captain and space for crew. Both the bathysphere and the bathyscaphe are used for studying the sea and seabed.
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