In How to know, about science and technology series we will provide you information about science and technology, We are in making part of series and every part will contain 8-10 scientific questions and answer !
HOW DOES A LIGHTNING CONDUCTOR WORK?
When lightning strikes, a giant A electric spark travels between the clouds and the ground. A lightning conductor is a long strip of metal that runs from the top of a building to the bottom It carries the electricity in the lightning safely to the ground.
Lightning strikes high buildings, so lightning conductors are fixed to them. The electric charge builds up more at the tip of the conductor. The conductor carries the electricity that flows between the ground and the clouds, so that no damage is done to the building,
WHAT DOES AN AERIAL DO?
To make a television or radio set work, it has to have an aerial. The aerial picks up the television or radio signals that come through the air. In the aerial, these signals change into tiny electric currents. Inside the set, these currents are turned into pictures and sound.
Television and radio signals are invisible rays that come from transmitters. When the rays meet a metal object, they produce very low electric signals. An aerial is designed to pick up as strong a signal as possible, so it may have to be pointed towards the transmitter.
HOW IS PETROL MANUFACTURED?
Petrol comes from the oil that is drilled from under the ground or under the sea. The petrol is distilled in a refinery. The oil is heated and goes to a tower. The petrol vaporizes and the vapour leaves the top of the tower. It is then cooled to give petrol.
Petrol is not the only product distilled from oil. It also produces paraffin or kerosene, and lubricating oils. These products vaporize with the petrol, but they have higher boiling points.
HOW IS LIQUID AIR PRODUCED
To make liquid air, air has to be cooled so much that the gases in the air turn to liquids. This happens at 200° C. Air is liquefied in machines that work like refrigerators, Liquid air is kept cold in vacuum flasks.
Air is liquefied by compressing it, removing the heat produced by compression, and then making it expand. The expansion causes the temperature to drop. By doing this several times, the temperature of the air falls to – 200° C and the nitrogen and oxygen gases in the air become liquid.
HOW IS COAL OBTAINED?
Coal is found in layers under the A ground. If the coal is near the surface, it is dug out of huge pits called open-cast mines. If the coal is deep underground, it is mined by digging shafts and tunnels to reach the coal.
Huge excavators are used to dig open-cast mines to reach the layers or seams of coal.
In a deep coal mine, shafts are sunk to reach the coal seams. Miners travel down in a cage to the coal face. There they use cutting machines to remove the coal, which is taken by conveyor belts along tunnels to an underground railway.
HOW IS COAL USED?
People who have fire-places in their A homes burn coal to heat the rooms. Coal is also used to make coal gas at
gas work. This gas is piped to homes in many towns and burned in cookers and heaters. Coke and products like plastics, drugs and dyes are also made from coal.
Coke is a fuel that is made from coal by heating it in an oven so that it does not catch fire. Instead it forms coke, coal tar and coal gas. Coke is used to make iron and steel, coal tar is surface roads and coal gas to supply homes and industry.
HOW DOES ELECTRICITY REACH THE HOMES
The electric current flows out to power lines. The power lines bring the electricity to homes and factories, The current travels along overhead or underground wires. It has to go through transformers and substations, where the current is changed to the lower voltage used in homes.
As the current leaves the power station, its voltage is increased to as much as 400,000 volts or possibly more.
The current is then fed into a network of high-voltage power lines which distribute electricity throughout the surrounding region
HOW DO WE USE SOLAR POWER?
We can use the Sun’s warmth to provide free heat. Solar panels on the roofs of houses trap the Sun’s rays. They warm water flowing through the panels. In this way solar power helps to produce hot water for washing and heating.
Solar panels are covered with glass to trap the Sun’s rays. Water runs through pipes in the panels and is warmed by the Sun’s heat. The warm water goes to a tank, and it may return to the solar panels to be heated some more. In this way, the Sun’s heat is used to warm the hot water supply of a house.
WHAT IS CEMENT MADE OF?
Cement is usually made from lime. A stone and clay, but chalk and sand may also be used. These materials are fed into a big machine that crushes them into small pieces and mixes them Then the mixture is heated in a kiln. When it cools, it is ground into cement powder.
The principal minerals in cement are lime, which comes mainly from limestone, and silica and alumina, which are provided by clay. Some iron ore is also used. After crushing and blending, the various ingredients are fed into a rotating kiln and heated to about 1500°C for several hours.
Also Read –
- Science And Technology Question & Answer – Part 1
- Science And Technology Question & Answer – Part 2
- Science And Technology Question & Answer – Part 4
- Science And Technology Question & Answer – Part 5
- Science And Technology Question & Answer – Part 6
- Science And Technology Question & Answer – Part 7
- Science And Technology Question & Answer – Part 8
- Science And Technology Question & Answer – Part 9
- Science And Technology Question & Answer – Part 10
- Science And Technology Question & Answer – Part 11
- Science And Technology Question & Answer – Part 12