TORNADO

Tornado is a localized, violently destructive windstorm occurring over land, especially in the Middle West, and characterized by a long, funnel-shaped cloud extending toward the ground and made visible by condensation and debris. Various types of tornadoes include the land spout, multiple vortex tornado, and waterspout. Waterspouts are characterized by a spiraling funnel- shaped wind current, connecting to a large cumulus or cumulonimbus cloud. They are generally classified as non-super cellular tornadoes that develop over bodies of water.


Tornadoes form in unusually violent thunderstorms when there is sufficient instability and wind shear present in the lower atmosphere. Instability refers to unusually warm and humid conditions in the lower atmosphere, and possibly cooler than usual conditions in the upper atmosphere. Wind shear in this case refers to the wind direction changing, and the wind speed increasing, with height. An example would be a southerly wind of 15 mph at the surface, changing to a southwesterly or westerly wind of 50 mph at 5,000 feet altitude. The
intense spinning of a tornado is partly the result of the updrafts and downdrafts in the thunderstorm.


Some steps can be taken to protect from their destruction, but sometimes tornadoes are so powerful that even these steps can be ineffective. These are usually huge F5 tornadoes, and, thankfully, they are rare. Open the windows of houses to equalize pressure within the house. Basements or tornado cellars are the best shelters in case of tornado.

A Tornado

THE LIGHTNING CONDUCTOR

             For centuries people did not know what lightning was. Ancient Indians believed that it was Lord Indra's weapon. The Romans believed that it was Jupiter's. All such myths were exploded in the 18th century by an American named Benjamin Franklin. One stormy day, he sent up a kite with a metal key tied to a string. He was out to prove that lightning was an electric charge coming down. After the kite had been up for some time, he brought his finger near the key. It gave off sparks. This happened because electric charge from a charged cloud had come down to the kite and had travelled down the wet string. It was a very dangerous experiment. Benjamin Franklin could have got killed if the charge had been more powerful.
            But now he had proof that lightning was an electric discharge. Putting this knowledge to use, he built the first lightning conductor and put it up on the house of a businessman in Philadelphia. During the monsoon when there are strong winds, the clouds rub against each other and develop electrical charges. Later, when the winds die down, the clouds stop moving around so much. If one such cloud stops over a building, the portion of the building nearest the cloud acquires opposite charge. When the charge is powerful enough it makes the charge from the cloud come down. This reults in lightning.
            The lightning conductor is nothing but a metal rod attached to the top of the building. The metal rod is connected to the earth by a copper wire. If a building has a lightning conductor and there is a charged cloud over the building, then it is the conductor which acquires the opposite charge because it is nearer to the cloud. This opposite charge is continuously sent down into the earth through the copper wire in the conductor. By not permitting the opposite charge to become powerful enough to make the charge from the cloud come down, the conductor prevents lightning.
             In the beginning, people did not want to use lightning conductors. They felt if God wanted to strike a particular building with lightning, it was not right for man to stop him.
             Nowadays, lightning conductors are a very common sight everywhere. Thunder and Lightning occur at the same time but we see the flash of lightning before we hear the peal of thunder. This happens because light travels faster than sound. If you are caught in the open during a thunderstorm, never stand under a tree because of its height will be the first to get hit by lightning.

Benjamin Franklin