Air - Long Answer Questions
Nitrogen (78%), Oxygen (21%), Argon (0.93%), Carbon dioxide (0.03%), and other gases/dust.
Plants need nitrogen to grow. They cannot take it directly from air. Bacteria in soil fixing it for them. It is the most plentiful gas.
Important: Green plants use it for photosynthesis. Problematic: Burning fuels releases excess CO2, causing the Greenhouse effect (Global Warming).
CO2 traps the heat radiated from the earth. Without it, earth would be too cold. Excess CO2 traps too much heat, raising global temperature (Global Warming).
Troposphere, Stratosphere, Mesosphere, Thermosphere, Exosphere.
Lowest layer (avg height 13km). The air we breathe is here. All weather phenomena (rainfall, fog, hailstorm) happen here.
Above Troposphere (up to 50km). Free from clouds/weather. Ideal for flying aeroplanes. Contains the Ozone layer.
Third layer (up to 80km). Meteorites burn up in this layer on entering from space.
Temperature rises very rapidly with height. Ionosphere is part of it (80-400km). Helps in radio transmission.
Uppermost layer. Very thin air. Light gases like helium and hydrogen float into space from here.
Hour-to-hour, day-to-day condition of the atmosphere (Hot, Humid, Windy).
The average weather condition of a place for a longer period of time (e.g., 30 years).
The degree of hotness and coldness of the air.
The incoming solar energy intercepted by the earth. It decreases from the equator towards the poles.
The pressure exerted by the weight of air on the earth's surface. Pressure falls rapidly as we go up. Air moves from high pressure to low pressure.
The movement of air from high pressure area to low pressure area.
1. Permanent winds (Trade winds, Westerlies). 2. Seasonal winds (Monsoon). 3. Local winds (Loo, Sea breeze).
Moisture in the air at any time. When air is full of water vapour, it is a humid day.
Water vapour rises, cools, condenses into droplets (clouds). When droplets become too heavy, they fall as rain (Precipitation).
Convectional rainfall, Orographic (Relief) rainfall, Cyclonic rainfall.
Air - Important Facts
Atmosphere is a blanket of air.
Nitrogen is 78% of air.
Oxygen is 21% of air.
Ozone protects from UV rays.
CO2 causes Global Warming.
Global warming causes sea level rise.
Troposphere is where weather happens.
Stratosphere contains Ozone layer.
Stratosphere is good for planes.
Mesosphere burns Meteorites.
Thermosphere reflects Radio waves.
Exosphere is the edge of space.
Temperature decreases with height in Troposphere.
Standard Lapse Rate: -6.5C per km.
Insolation is max at Equator.
Insolation is min at Poles.
Temperature creates Pressure differences.
Hot air rises (Low Pressure).
Cold air sinks (High Pressure).
Wind moves High -> Low.
Barometer measures Pressure.
Thermometer measures Temperature.
Rain Gauge measures Rainfall.
Wind Vane shows Wind Direction.
Loo is a hot local wind in India.
Monsoon is a seasonal wind.
Trade winds blow constantly.
Cyclones can be destructive.
Odisha Super Cyclone (1999) killed thousands.
Precipitation comes as rain, snow, hail.
Plants help preserve water.
Cutting trees causes floods.
Jet planes leave white trails (condensed moisture).
Humidity makes us feel sticky.
Clothes take longer to dry on humid days.
Air pressure is highest at sea level.
Astronauts wear space suits due to lack of pressure.
Argon is 0.93% of air.
Wind is named after direction it blows from.
Westerly blows from West.
Climate is long-term average.
Weather is short-term state.
Met dept predicts weather.
Degree Celsius is unit of temperature.
Water boils at 100C.
Water freezes at 0C.
Anders Celsius invented the scale.
Air - Important Dates/Terms
Oct 1999: Odisha Cyclone