Air for Breathing and Combustion

The air around us is what is commonly known as the atmosphere of the Earth. The atmosphere is a huge blanket of air that envelopes the planet. It provides us with the air for respiration and shields us from the direct sun’s rays which can be damaging.  

The atmosphere consists of foremost 78% nitrogen, 21% oxygen, 0.93% argon and 0.03% carbon dioxide as well as other gases such as helium, ozone, argon and hydrogen in much lesser quantities.

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Why Air is Necessary?

  • If the world had no atmosphere, it would be an extremely hostile, cold climate. The atmosphere and air around us help regulate and moderate the temperature of the Earth. 

  • Air is essential because it consists of the gases essential to sustain all life forms; humans, plants, animals and other organisms.

  • Air is crucial as it supports water to transition from one state to another through the process of the water cycle. The water cycle warrants that the planet doesn’t run out of the water as it is a valuable resource and everyone receives it. Air replenishes lakes, rivers and other waterways to ensure everyone gets water.

Why Air is Vital for Respiration? 

The two main gases involved in the process of respiration are oxygen, and carbon dioxide, all the living organisms on Earth are able to live because of these two gases and all of us are dependent on them. The oxygen component is used by all living beings to react with glucose (a type of sugar that you get from food) to produce energy for different activities. This energy is used for growth, development and all other activities. Carbon dioxide and water are released as end products of respiration. Plants, on the other hand, breathe in carbon dioxide to convert the chemical energy using sunlight and release oxygen and glucose. This is the process in which they manufacture their own food, which is called ‘photosynthesis’. 

Why Air is Necessary for Combustion?

Combustion is a high-temperature chemical process which releases a lot of energy which occurs between a fuel and an oxidant (oxygen-containing substance); mainly the oxygen present in the atmosphere. Combustion occurs at high temperatures, and emits energy to the surroundings in the form of light and heat. This is why flames appear when combustion happens.

Methane is an important part of combustion; it combines with oxygen in the atmosphere and emits a coloured flame. The energy from the reaction can be utilised to heat things, cook food, produce electricity and also power vehicles.

Why Air is Vital for the Regulation of Temperature?

Air helps in the formation of winds. During summers, the land gets heated up much faster than the oceans; the temperature of the Earth’s surface rises rapidly. The air above the land is hot and thus rises, and the cold air from the sea surface moves and forms a layer above the land, thus not letting the temperature rise very high. This creates wind and helps regulate the temperature. The air and the atmosphere also form a protective layer around the planet and protect it from the excessive UV rays of the sun, thus, cooling the Earth down in the process.

Why Air is Needed for Burning? 

Combustion is very important since it helps not only emit energy but also produce light as well. It is the primary source of energy and is essential to all life forms. 

To explain how and why air is important for burning, let us do an experiment i.e. the candle and glass experiment. For this experiment, you will require

  • One Candle

  • Candle Lighter or Matches (adult supervision is recommended)

  • A Glass jar or a drinking glass

  • Ceramic dinner plate or wooden board (optional)

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  • Place the candle on the wooden board and light it using the candle lighter or matches. 

  • Watch the candle for a few moments and observe that it is burning simply and continuously, and the flame is not going off.

  • Now get the glass jar, it should be a transparent one, through which you can easily observe the candle and its flame.  

  • Place the glass jar upside down, so that the candle is inside the glass jar and covers it entirely. 


  • You will see that the flame will get extinguished in a few seconds after keeping the glass jar.

  • This happens because when you keep the jar, the oxygen available inside the jar is limited, and thus when it is all used up, the flame will go off.

  • You can also observe small droplets of water along the inner surface of the glass jar. This shows that combustion releases water as a by-product. 

This experiment tells us that combustion is not possible without oxygen and that water is a by-product of the chemical reaction.

FAQ (Frequently Asked Questions)

Q1. What Do the Other Gases Present in the Air Do?

Ans. Nitrogen is more abundant in the atmosphere than oxygen. It is required by all living being; humans, animals, and plants for the production of proteins and other essential building units used as a source of energy. It is utilised for numerous commercial purposes. 

Uses of the oxygen we have already discussed; respiration, combustion and regulation of temperature. 

Argon is a colourless, odourless, and tasteless inert gas. It is utilised in gas-filled electric light bulbs, radio tubes and as an inert environment for arc-welding metals, such as aluminium and stainless steel; and for the production and of various metals, such as titanium, and uranium; and for developing semiconductor crystals, such as silicon and germanium.

Carbon dioxide is used by plants to manufacture and store their food, as discussed earlier. 

Q2. What is the Meaning of Air Pollution and its Effects?

Ans. Air pollution is the contamination of air by the addition of particles and gases. The addition of pollutants can have adverse effects which can vary from serious disease risks to the average temperature of the planet rising. Pollutants such as soot, smoke, pollen, methane, and carbon dioxide are deadly to the environment.

This pollution can occur through improper disposal of waste gases, deforestation, forest fires and soil erosion. 

The consequences are deadly ranging from respiratory diseases to nervous system damage and harm to liver, spleen and blood, and constant fatigue and headaches.