Air as a Natural Resource - Class 5 Notes & Olympiad Questions

Air

Air is indeed a natural resource that is vital for sustaining life on Earth. It is a mixture of gases, primarily nitrogen and oxygen, that makes up the Earth's atmosphere. Air plays a crucial role in supporting the survival of living organisms.

Some important aspects of air as a natural resource:

1. Oxygen Supply: Air provides the oxygen necessary for the respiration of humans, animals, and many other organisms. Oxygen is essential for breathing and respiration.

2. Heat and Energy: Air is super important because it helps things burn and gives us heat and energy. We need air when we burn things like fuels in power plants, vehicles, and heating systems to generate power and keep things warm.

3. Provide Carbon Dioxide: Plants need carbon dioxide to carry out photosynthesis. It is essential for them to make their own food and release oxygen for us to breathe.

4. Air Quality: The quality of air affects human health and the health of ecosystems. Clean air is essential for respiratory well-being and for preventing respiratory diseases. Contaminated air, on the other hand, can have harmful effects, especially due to pollutants and particulate matter.

5. Natural Processes: Air plays a vital role in various natural processes, such as wind dispersal of seeds and pollen, transportation of water vapour, etc.

6. Recreation and Aesthetics: Air provides opportunities for outdoor activities, leisure, and enjoyment of natural landscapes. Fresh air and clean environments contribute to the overall well-being and mental health of individuals.

Properties of Air

1. Air fills up space: Air is a gas that fills the space around us. When we see an empty room, it's actually filled with air, even though we can't see it. It's like invisible stuff that takes up space everywhere.

2. Air gives shape to things: Air can fill up things like balloons, making them expand and take on a specific shape.

3. Air is required for burning: When we light a fire or a candle, we need air for it to burn. Air contains oxygen, which is necessary for combustion. It's like the ingredient that makes things catch fire and burn. Without air, fires wouldn't be able to stay lit.

4. Air has mass and weight: Even though we can't see or feel it, air actually has mass. Mass is what gives things weight and makes them take up space. The weight of the air is not something we notice, but it's there all around us, pressing down on everything.

5. Air can make things move: Air can exert force on objects, causing them to move. For example, when you blow air into a sail or a balloon, it creates pressure and makes them move. Air can also make things like leaves, kites, or paper flutter in the wind.

6. Air is colourless and odourless: Unlike some substances that have distinct colours or smells, air doesn't have any colour or odour. It's why we can't see or smell it, even though it's all around us.

Atmosphere

a) The atmosphere is like a big blanket of air that surrounds the Earth. It is held in place by the Earth's gravity.
b) The atmosphere is made up of a mixture of different gases, with most of them being closer to the Earth's surface.
c) The main gases in the atmosphere are nitrogen (78%) and oxygen (21%), which are essential for life.
d) There are also smaller amounts of other gases like argon, carbon dioxide, hydrogen, krypton, helium, ozone, and neon.
e) In addition to gases, the air in the atmosphere also contains water vapour, dust, and smoke. These things can affect the weather and air quality.
f) The atmosphere is divided into several layers, each with its own density, thickness, and temperature.

Layers of the Atmosphere

The atmosphere can be divided into different layers with distinct characteristics:

1. Troposphere

a) The closest layer to the Earth's surface.
b) Most of the weather happens here, like rain, storms, and clouds.
c) Extends about 15 kilometres over the equator and 10 kilometres above the poles.
d) The temperature gets colder as you go higher up.

2. Stratosphere

a) Above the troposphere.
b) No weather phenomena occur here.
c) It's about 35 kilometres thick.
d) Aeroplanes fly in this layer.
e) Contains the ozone layer, which protects us from harmful ultraviolet rays from the sun. (Harmful effects of UV rays include sunburn, skin ageing, increased risk of skin cancer, and damage to the eyes.)

3. Mesosphere

a) The middle layer of the atmosphere.
b) Known for meteor showers.
c) It's the coldest part of the atmosphere.

4. Thermosphere

a) Contains very little air.
b) The temperature rises as you go higher up.
c) At the top, temperatures can reach extremely high levels, like over 1000 degrees Celsius.
d) It's the hottest layer of the atmosphere.

5. Exosphere

a) The outermost layer of the atmosphere.
b) Extends up to 10,000 kilometres from the Earth's surface.
c) Artificial and weather satellites orbit the Earth in this layer.