In a Nutshell

Atmosphere

A gravity-held blanket in constant motion

3.1 What Is the Atmosphere? Gravity holds a blanket of gases that supports and protects life.

3.2 Composition Nitrogen (78%), oxygen (21%), other gases, water vapour and dust.

3.3 Structure Troposphere, stratosphere, mesosphere, thermosphere, exosphere.

3.4 Weather and Climate Temperature, humidity, precipitation, pressure and wind interact.

3.5 Seasons in India Winter, summer, monsoon and post-monsoon, per the IMD.

3.6 Monsoon Seasonal wind reversal that controls Indian agriculture and life.

3.7 Climate Change and Carbon Footprint Human activity raises greenhouse gases; we can reduce our footprint.

3.8 Punjab Floods 2025 A case study of monsoon, rivers, human planning and disaster risk.

Atmosphere: A blanket of gases surrounding the Earth, held in place by gravity.
Gravity: The force of attraction that pulls objects, like gases, towards the Earth.
Insolation: The incoming solar energy from the Sun that the Earth receives.
Altitude: The height of a location above mean sea level.
Troposphere: The lowest atmospheric layer, up to about 12 km, where nearly all weather occurs.
Stratosphere: A stable, cloud-free layer up to 50 km that contains the ozone layer.
Mesosphere: The middle layer, up to about 80 km, where most meteors burn up.
Thermosphere: A very hot layer, 80 to 700 km up, where auroras and radio waves occur.
Exosphere: The outermost layer, with very thin air fading into outer space.
Weather: The hour-to-hour and day-to-day condition of the atmosphere.
Climate: The average weather of a place over a long period, usually 30 years or more.
Humidity: The amount of water vapour present in the air.
Precipitation: Water falling from the atmosphere as rain, drizzle, snow, sleet or hail.
Atmospheric Pressure: The pressure exerted by the weight of air on the Earth’s surface.
Wind: The movement of air from a high-pressure area to a low-pressure area.
Monsoon: The seasonal reversal of wind direction during a year.
Climate Change: Long-term changes in weather patterns, caused mainly by human activity.
Carbon Footprint: The total greenhouse gases released by a person’s energy use, transport and consumption.

Class 6