Air

Summary Notes

Atmosphere: Our earth is surrounded by a huge blanket of air called the atmosphere.

Use of atmosphere:

• Provide us the air we breaths
• Protect us from the harmful effects of Sunrays.
• Without the atmosphere, we could be burned during the day and get frozen during the night; Atmosphere has made the earth liveable.
• Without the atmosphere, the water cycle can not be complete.

What is the greenhouse gas effect?
Carbon dioxide in the atmosphere traps the heat radiated from the earth and makes the earth warm at night. This is called the greenhouse gas effect.

What is global warming?
When the level of Co2 in the atmosphere increase due to the burning of fossil fuels and other means; at the result, it is able to trap more heat in the atmosphere and resulting in the global temperature on the earth gets rise; this phenomenon is called global warming.

Effects of global warming:

• The rise in global temperature
• Cause snowmelt from glaciers; as a result, sea-level rise
• The temperature of seawater increases; water expands when it is warm; as a result, the sea level rises.
• Submergence of coastal plains and islands due to sea level rising.
• Drastic changes in the climate of a place; lead to the extinction of some plants and animals in the long run.

Composition of atmosphere:

• Nitrogen: 78 %
• Oxygen: 21 %
• Argon: 0.93 %
• Carbon dioxide: 0.03 %
• All other: 0.04 %

Name the different layers of the atmosphere.?

There are five different layers of the atmosphere:

1. Troposphere
2. Stratosphere
3. Mesosphere
4. Thermo or ionosphere 
5. Exosphere

Layers of atmosphere

Troposphere: 

The following are the characteristics of the troposphere:

• Height of the troposphere decrease from the equator ( 18 km ) to the poles( 11 km)
• All the weather phenomena such as cloud formation, thundering, etc are found in this layer.
• Greenhouse gases found 
• Air Pressure and temperature decrease when we go up from the earth in the troposphere
• Vertical movement of air due to heating 
• 75% of the air in the atmosphere is found in this layer.
• 99% of water vapors are found in this layer.
• Tropo pause is found at the top of the troposphere.

Stratosphere:

The following are the characteristics of the stratosphere:

• This is the second layer of the earth and goes up to 50 km.
• The ozone layer is found at the bottom of the stratosphere.
• Temperature increases with height due to the absorption of U-V rays by the ozone layer.
• Polar stratospheric clouds are found in this layer.
• Calm atmosphere.
• In the lower stratosphere, commercial planes and jets fly

Mesosphere:

The following are the characteristics of the Mesosphere:

• This is the third layer and goes up to 80 km.
• Most Meteor burn in this layer
• Temperature decrease with height
• -the 90-degree temperature is in menopause( topmost)
• Thermosphere or Ionosphere

Thermosphere:

The following are the characteristics:

It extends from 80 to 1000 km

• High energy such as X-Ray and UV radiation is absorbed and temperature increase with height
• Temperature riches up to 1500 degrees but you will feel cold because of very low air molecules.
• Colorful Aurora Borealis and Aurora Australia can be seen here.
• The international space station is in this layer.

Exosphere:

• The exosphere is up to half the distance from the earth to the moon.
• A very very low atmospheric molecule made of mostly Helium & Hydrogen
• It absorbed most of the harmful radiation 

Weather and Climate

Weather:
Weather is hour to hour and day-to-day condition of the atmosphere.

Climate:
The sum of the weather condition of a place for a very long period of time (more than 30 years) is the climate of that place.

Insolation:
Insolation is the incoming solar energy intercepted by the earth. The amount of insolation decrease from the equator towards the poles; therefore temperature decrease in the same manner. That's why the pole is covered with snow.

Air pressure

Why do we not feel the air pressure?
Air press us from all direction and our body exert counter pressure.
Air pressure is exerted by the weight of air on the earth's surface. When we go up, air pressure falls rapidly. Air pressure is highest at sea level.

Low-pressure area: It is created by the heating of air. Air rise in the low-pressure area.
Heavy air sink and create a high-pressure area.

Wind:
Movement of air from a high-pressure area to a low-pressure area; this movement is called wind.
A wind is named after the direction from which it blows. For example, Westerly winds blow from the west.

Three types of winds:

• Permanent winds
• Seasonal Winds
• Local winds

Permanent winds: These blow constantly through the year in particular directions.

• Trade winds
• Westerlies
• Easterlies

Seasonal winds:
It changes the direction in different seasons. For example, Monsoon.

Local winds:
Winds blow in a particular direction in a particular area.
For example, land & sea breeze
Loo, dry and hot air in the northern area.

Moisture:
When the water evaporated from land and water bodies, this evaporated water is called moisture.

Humidity:
Moisture in the air at any time is called known humidity.

How cloud formed?
When water vapor rises, it starts cooling and water vapor condenses and forms clouds.

Types of rainfall:

• Orographic
• Conventional
• Cyclonic rainfall

Jet plans leave whitetail in the sky due to condensing moisture above the height.

Exercises

Q1. What is the atmosphere?
Answer.
The huge blanket of air around the earth is called the atmosphere.

Q2. Which two gases make the bulk of the atmosphere?
Answer.
Nitrogen( 78 %) and Oxygen(21%)  are two major gases in the atmosphere.

Q3. Which gas creates a greenhouse effect in the atmosphere?
Answer.
Co2, Carbon dioxide gases create a greenhouse gas effect by trapping the sun's heat in the atmosphere.

Q4. What is the weather like?
Answer.
Weather is an atmospheric phenomenon of a particular place at a particular time. Weather changes hour to hour and day to day basis.

Q5. Name three types of rainfall?
Answer.
The following are the three types of rainfalls.

• Orographic 
• Conventional rainfall
• Cyclonic rainfall

Q6. What is air pressure?
Answer.
The total weight of air in a particular place is called air pressure. 
High air pressure is found at the sea surface.
A low air pressure area is found in high-temperature areas.

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