Science 5 Marks Questions

In case cyclone approaches our village or town, we can help our neighbours in following way:

• We should not ignore the warnings issued by the meteorological department through TV, radio, or newspapers.
• We should make necessary arrangements to shift the essential household goods, domestic animals and vehicles, etc. to safer places.
• Avoid driving on roads through standing water, as floods may have damaged the roads; and keep ready the phone numbers of all emergency services like police, fire brigade, and medical centres.
• Do not drink water, that could be contaminated. Always store drinking water for emergencies.
• Do not touch wet switches and fallen power lines.
• Do not go out just for the sake of fun.
• Do not pressurise the rescue force by making undue demands.
• Cooperate and help your neighbours and friends.

The equator receives the Sun's direct rays. Here, air is heated and rises, leaving low pressure areas behind. Moving to about thirty degrees north and south of the equator, the warm air from the equator begins to cool and sink. Between thirty degrees latitude and the equator, most of the cooling sinking air moves back to the equator. The rest of the air flows toward the poles.

Lightning is a bright flash of electricity produced by a thunderstorm. All thunderstorms produce lightning and are very dangerous. If you hear the sound of thunder, then you are in danger from lightning. Lightning kills and injures people and properties.

Lightning is an electric current. Within a thundercloud way up in the sky, many small bits of ice frozen raindrops bump into each other as they move around in the air. All of those collisions create an electric charge. After a while, the whole cloud fills up with electrical charges. The positive charges or protons form at the top of the cloud and the negative charges or electrons form at the bottom of the cloud. Since opposites attract, that causes a positive charge to build up on the ground beneath the cloud. The grounds electrical charge concentrates around anything that sticks up, such as mountains, people, or single trees. The charge coming up from these points eventually connects with a charge reaching down from the clouds and - zap - lightning strikes!

When air moves gently (low speed), it is called a breeze while when it moves violently (high speed), it is called a storm. When the pressure of air drops, it indicates the possibility of a storm. The swift movement of the falling water along with the rising warm air producing sound, lightning, heavy rain and strong wind is called thunderstorm. It develops in hot and humid tropical areas like India and is accompanied by heavy rains or hail. Thunderstorms are produced by the dark clouds which form at fairly low altitude in the atmosphere. In the tropical area, the air gets warmed up and makes it to rise, whereas humidity provides the water vapour for the formation of cloud. Therefore, it can be said that to occur a thunderstorm, it requires moisture, rapidly rising warm air and sea breeze or mountains.