AIR, WINDS AND CYCLONES
Air : Air is the mixture of nitrogen, oxygen, carbon dioxide, water vapour, inert gases and dust particles occupied around the earth.
Air expansion : On heating, the air expands and becomes lighter.
Cyclone : A very low pressure system with a very high speed winds that revolves around, is called a cyclone.
Low pressure : Increased wind - speed, is accompanied by a reduced pressure. Also warm air rises up causing low pressure.
High pressure : Relatively compared with low pressure, high pressure area on the surface of earth.
Anemometer : The instrument that measures the speed of wind is called as anemometer.
Satellites : A satellite is a body revolving round another body of large mass. It hasb ecome easier to study cyclones with the help of advanced technology like artificial satellites.
Radar : It is the acronym of "Radio Detection and Ranging".
Main Points
- The air around us is rarely still.
- Air exerts pressure.
- Air expands on heating.
- Hot air is lighter than cold air.
- We get land breeze and sea breeze.
- Regions close to the equator gets more heat from the sun.
- Increased wind speed is accompanied by a reduced air pressure and this aids rains.
- Farmers in our country mainly depends on rains for their harvests.
- Cyclones are a form of violent storms on earth.
- Tropical cyclones are like giant engines that use warm moist air as fuel.
- Factors like wind speed, wind direction, temperature and humidity contribute to the development of cyclones. Cyclones can be very destructive.
- Wind speed plays an important role in the formation of storms.
- Air is every where.
- The moving air is called wind.
- Air around us exerts pressure.
- Air expands on heating and contracts on cooling.
- Warm air rises up whereas comparatively cooler air tends to sink towards the earth's surface.
- As warm air rises air pressure at the place is reduced and the cooler air moves into that place.
- Uneven heating on the earth causes wind movements.
- Cyclones may be caused due to wind travelling at high speed due to difference in air pressure.
- It has become easier to study cyclones with the help of advanced technology like satellites and radars.