Monday, December 8, 2008

Lightning and Thunderstorms

Clouds are made up of water droplets together with the dust in the atmosphere at an altitude of 1 to 16 km. These droplets move downward while the air currents upwards. These movements cause different charges. Lightning occurs when the oppositely charged clouds collide with each other. Lightning can be seen as a streak of bright light and sound. There are of very high voltage(minimum 2 million) and they rush towards the ground through the moisture filled air.

Lightning strike could destroy life and property. It is therefore necessary to take measures to protect ourselves. During lightning and thunderstorm a house or a building is safe place. If you are travelling by car or by bus, you are safe inside with windows and doors of the vehicle shut.
Lightning can strike telephone cords, electric wires and metal pipes. Avoid bathing suring thunderstorms so that you can avoidcontact with the running water.

Lightning Strikes the Capitol Building in Washington

Perhaps 90 percent of the lightning flashes are said to be negative and the remaining, positive. The average interval between successive lightning strokes is 0.02 sec and the average flash lasts 0.25 sec.

It is said that lightning flashes consist of multiple events.There are 42 flashes which are preceded by a leader stroke.Ball lightning is a rare phenomenon in which the discharge takes the form of a slowly moving, luminous ball that sometimes explodes.

The lightning surges in there own path towards the earth, can strike power lines and antenna and pass through wires to the terminal equipments such as TV.the huge voltage current, even through of short life,can damage the electrical components and electronic circuits which are usually designed for low power.

Nearly 40 percent of all farm fires and 75,000 forest fires are started due to lightning. However, lightning enriches the soil. This is by forming nitrogen-dioxide which dissolves in rain water and forms nitric acid, which is and essential nutrient for plant growth.

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