Introduction
Air is a gas that is all around us and is necessary for both breathing and combustion. In this article, we will discuss the properties of air that make it so important for these two processes. Air is made up of different gases, including nitrogen, oxygen, and argon. These gases are necessary for both breathing and combustion because they each have unique properties that allow them to function in these processes.
Nitrogen is the most common gas in air, making up about 78% of the total volume. It is a non-flammable gas that is inert, meaning it does not support combustion. Oxygen is the second most common gas in air, making up about 21% of the total volume. It is a flammable gas that is necessary for combustion. Argon is a non-flammable, inert gas that makes up about 1% of the total volume of air.
Inhaling and exhaling are both processes that allow us to get the oxygen we need from the air around us. Breathing is a vital process for people because it keeps us alive so we can continue to function. In this lesson, we will discuss how humans breathe and what role air plays in the process. When we breathe, the air enters our lungs, where it is diffused into our bloodstream. The oxygen in the air is then transported to all of the cells in our body, where it is used to produce energy. The carbon dioxide that is produced by our cells is then transported back to our lungs and exhaled.
Air is necessary for breathing because it provides us with the oxygen we need to produce energy. Complex molecules called hydrocarbons are necessary for combustion. When a hydrocarbon is burned, it reacts with oxygen to produce carbon dioxide and water vapour. The carbon dioxide is then expelled from the body, and the water vapour is exhaled. Air is necessary for combustion because it provides us with the oxygen we need to react with the hydrocarbons.
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 about 78% of nitrogen, 21% of oxygen, 0.93% of argon and 0.03% of carbon dioxide as well as other gases such as helium, ozone, argon and hydrogen in much lesser quantities.
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Why Is Air 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 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 Is Air Necessary for Combustion?
Combustion is a high-temperature chemical process that 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 is Air 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 to 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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Method
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.
Result
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.
Conclusion
This is how air is important for different biological processes, burning, and regulation of temperature. Focus on the prime concept of the usage of air and learn what role is played by it in different processes.
FAQs on Air for Breathing and Combustion
1. What is air and what are its main components?
Air is the mixture of gases that forms the Earth's atmosphere, essential for life. Its primary components are Nitrogen (N₂), making up about 78%, and Oxygen (O₂), which is approximately 21%. The remaining 1% consists of other gases, including Argon (Ar), Carbon Dioxide (CO₂), and trace amounts of neon, helium, and methane, along with variable amounts of water vapour and dust particles.
2. Why is oxygen in the air essential for breathing?
Oxygen is essential for breathing because it enables cellular respiration. When we inhale, oxygen enters our lungs and is transported by the blood to every cell in our body. Inside the cells, oxygen acts as a key reactant to break down glucose (from food) and release energy. This energy powers all vital functions, from muscle movement to brain activity. Carbon dioxide, a waste product of this process, is then exhaled.
3. How does air support the process of combustion?
Air supports combustion, or burning, by providing the necessary oxygen. Combustion is a chemical reaction in which a substance reacts rapidly with an oxidant (usually oxygen) to produce heat and light. Without a continuous supply of oxygen from the air, a fire cannot be sustained. This is why covering a candle with a glass jar extinguishes the flame—it uses up the available oxygen and the combustion process stops.
4. If nitrogen is the most abundant gas (78%), why can't our bodies use it directly from the air for breathing?
While we inhale a large amount of nitrogen with every breath, our bodies cannot use it directly because it is an inert gas in its atmospheric form (N₂). Our lungs and blood are biologically adapted to bind with and transport reactive oxygen molecules. The strong bond between nitrogen atoms makes it unusable for respiration. Instead, humans and animals get the essential nitrogen needed for building proteins by consuming plants or other animals that have absorbed nitrogen from the soil and converted it into usable compounds.
5. What is the main difference between breathing and respiration?
Breathing and respiration are often confused but are distinct processes:
- Breathing is the physical mechanism of inhaling air into the lungs (gaining oxygen) and exhaling air out (expelling carbon dioxide). It's a mechanical process.
- Respiration is the chemical process that occurs inside the body's cells. It uses the oxygen obtained from breathing to break down food and release energy, producing carbon dioxide as a waste product.
6. What is the importance of carbon dioxide in the air for plants and animals?
Carbon dioxide (CO₂) plays a crucial, dual role. For plants, it is a vital raw material for photosynthesis—the process where they convert light energy, water, and CO₂ into food (glucose) while releasing oxygen. For animals, CO₂ is a waste product of respiration. However, it also helps regulate the pH of the blood and stimulates the brain's respiratory centre, helping to control the rate and depth of breathing.
7. What would happen if the percentage of oxygen in the air was much higher, for example, 30%?
A significantly higher oxygen concentration, such as 30%, would make the environment dangerously flammable. Fires would start much more easily and burn with greater intensity, making them incredibly destructive and difficult to control. While it might seem beneficial for breathing, prolonged exposure to high oxygen levels can cause oxygen toxicity in humans and animals, a condition that damages cells in the lungs, eyes, and central nervous system. The current 21% level represents a critical balance that supports life while maintaining relative chemical stability.
8. How are the processes of respiration and combustion similar, yet different?
Respiration and combustion are similar as both are oxidation processes that require oxygen and release energy. However, they differ significantly in their execution:
- Similarity: Both processes use oxygen to break down a fuel (food in respiration, substances like wood in combustion) and produce carbon dioxide and water as by-products while releasing energy.
- Difference: Respiration is a slow, controlled, low-temperature biological process occurring in multiple steps within living cells. Combustion is a fast, uncontrolled, high-temperature chemical reaction that releases energy rapidly as heat and light.
9. What is the purpose of other gases in the air, like argon?
Gases like argon are chemically inert, meaning they do not easily react with other elements. While they play no direct role in breathing, this property is very useful in industrial applications. For example, argon is used inside incandescent light bulbs to prevent the hot tungsten filament from reacting with oxygen and burning out. It is also used in welding to create a non-reactive shield around the molten metal, ensuring a clean and strong weld.
