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What is a Geostationary Orbit?

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Artificial satellites sent from the Earth orbit around the earth. The ones near the Earth orbit faster than the ones far away. A satellite 35,900 Km above the Earth's surface, takes 24 hours to orbit once. The satellite is always above the same point on the Earth's surface as the planet rotates. Geostationary orbit is also called as geosynchronous ' orbit. Such satellites are used to receive telephone and television signals and retransmit them over long distances.
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When were the First Mechanical Clocks Made?

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The first mechanical clocks are believed to have been made in China in 1088 AD. Later in 1200s, they were first made in Europe. Such clocks made in Europe were driven by a weight on the end of a cord wound round a drum. As the drum rotated, it turned the hands of the clock. The earliest known clock was made in Spain in 1276 AD and the oldest mechanical clock that still works is in Salisbury cathedral in Britain. It was made in 1368. These clocks had devices called escapements to keep the hands turning at the correct rate, so that the clocks depicted the correct time.
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When were the First Spinning Machines Invented?

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People in the olden days used to spin thread by hand . They pulled fibres out of cotton and wool and twisted them together into thread. Spinning machines were invented in Britain in the 1700s. These machines had rollers turning at different speeds to twist the fibres into yarn. James Hargreaves in 1764 produced the first successful spinning machine. It was the hand-powered jenny which produced thin yarn. Richard Arkwright's water frame of 1769, powered by water wheels, gave a sturdy thread. Samuel Crompton combined these two spinning machines in 1779 , to make the spinning mule, which could spin many kinds of yarn. These machines were the precursors of the Industrial Revolution . 
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Where are Baobab Trees Found?

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T he baobab tree is a native of tropical Africa. It is a very strange looking tree which has a barrel like trunk that can reach 30 feet or more in diameter and its height is not proportionately great. The fruit of this tree is large, gourd like and woody which contains a pleasant and cool tasting juice . A strong fibre from the bark is used to make ropes and cloth. The wood is soft and light and is used to construct houses.
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Why does Mistletoe Grow on Trees?

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M istletoe is a plant which grows on branches of higher trees. It is a partial parasite since it has green leaves containing chlorophyll and can make its own food by photosynthesis. It takes the water and minerals it needs from the sapwood of the host tree. It is found growing on trees like apple, hawthorn, willow, poplar and lime . The seeds of mistletoe are spread by birds and once the seed germinates on the host tree, it develops haustorium . The haustorium is a tough structure and ensures of a regular supply of water and nutrients from the sapwood of the host to the mistletoe. The plant then develops a clamp like structure on the tree to be placed firmly.
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