Everything About The Oxygen Cycle For Kids: An Element For All | Kidadl


Everything About The Oxygen Cycle For Kids: An Element For All

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Oxygen is the most common element; it makes 21% of the Earth's atmosphere.

Millions of years ago, the Earth's atmosphere was similar to Mars and Venus. It was made up of carbon dioxide 95%, nitrogen 2-3%, and oxygen was less than 1%.

It mainly had silicate, iron, and other elements during its origin. It took more than millions of years for the Earth to develop into its present form. Within the Milky Way galaxy, reactions between the dust and gas clouds occurred. Also, the meteorites' strikes grew the size of the Earth. Then volcanoes began to form, which emitted important gases, ash, and lava.

Due to the continuous reactions of the radioactive elements, the Earth became hotter and hotter. The iron started melting and reached the center of the Earth. Eventually, the iron accumulated at the Earth's center, and the core became hard. Today the planet earth contains 21% oxygen, 3% water vapor, and 79% nitrogen.

If you enjoyed reading our article, you would also love to read about whether plants make oxygen and why we need oxygen? Here on Kidadl.

Components Of Oxygen Cycle

For life on Earth, we must have oxygen. Most oxygen is continuously being used and created on Earth by different processes, and it is a biogeochemical cycle. Oxygen contains 21% of the Earth's atmosphere, and it is an odorless and colorless gas. Oxygen is present in the Earth's crust, water, air, and carbon dioxide. The oxygen cycle is the circulation of oxygen gas in the three main reservoirs atmosphere, biosphere, and lithosphere.

Plants create oxygen by a process known as photosynthesis. To create oxygen, plants require sunlight and carbon dioxide to produce energy and release most oxygen into the air. The living beings breathe oxygen in and breathe carbon dioxide out, and the plants use this carbon dioxide and thus complete the oxygen cycle. Oxygen gas is unevenly distributed on planet Earth, and it is the most important element for the survival of life on this planet. It is present in the air that we breathe in and the water we drink, and it is also present in compound form in some metals. The main components of the oxygen cycle are present in the atmosphere (air), biosphere (where plants and animals live), and lithosphere (outermost shell of the planet Earth).

Along with various gases, 21% is oxygen present in the molecular form in the atmosphere, and only 0.35% of oxygen gas is present in the Earth's atmosphere. Oxygen is released into the atmosphere by a process known as photolysis, in which the sunlight reacts with water vapor and other oxides. In the biosphere, all plants and animals live. Around 21% of oxygen is present in the biosphere in organic molecules. The exchange of oxygen between plants and animals occurs by a process known as photosynthesis and respiration. In photosynthesis, plants require sunlight and carbon dioxide to create oxygen, and the sunlight reacts with carbon dioxide. In the lithosphere, around 46% of oxygen is present, and it is present in mineral deposits, oxides, and organic content. The oxides of metals are formed as the chemically active elements are exposed to oxygen. Example: magnesium oxide.

The hydrosphere is the art of the Earth's surface covered with water. Around 70%-80% of the oxygen comes from the ocean, and this dissolved oxygen is present in the water molecules responsible for the survival of the aquatic world.


As a child, you must know that the air we breathe is oxygen, and we need the right oxygen level to survive. All living things need oxygen, and the oxygen gas is odorless, colorless, and tasteless. The main processes responsible for the oxygen cycle are photolysis, photosynthesis, and respiration. Photolysis is when the sunlight reacts with water vapor and other oxides to release oxygen.

Photosynthesis is when the plants and trees in sunlight and carbon dioxide prepare their own food and produce energy while releasing oxygen into the atmosphere. So plants prepare their own food to create energy and release oxygen as a by-product into the air. Respiration is the process in which humans and animals consume oxygen from the atmosphere to break the food molecules into simpler forms while releasing carbon dioxide into the atmosphere, along with the release of energy known as respiration. In the human blood, hemoglobin carries oxygen to different body parts through the blood vessels. How the oxygen works in the human body is truly a miracle?

Organisms that require oxygen for survival and reproduction are known as aerobic organisms. Those organisms that do not require are known as anaerobic organisms. The two main processes involved in the oxygen cycle are photosynthesis and respiration. These two processes link the water cycle, oxygen, and carbon cycle.


The oxygen cycle works mainly to maintain the oxygen level in the atmosphere. The oxygen cycle starts with photosynthesis in sunlight and carbon dioxide; oxygen is released into the atmosphere. Humans and animals breathe in oxygen from the atmosphere and breathe out carbon dioxide. The oxygen cycle converts sunlight into heat, and the plants use this carbon dioxide, and the process repeats.

The oxygen cycle is known as the biogeochemical cycle; the steps involved in the oxygen cycle are reversible. In the atmosphere, the photolysis process occurs in which water vapor and other oxides like nitrous oxide are broken down in the presence of sunlight to release oxygen. In the biosphere, two steps are involved, photosynthesis and respiration. Photosynthesis is when the green plants and trees prepare their food in sunlight and carbon dioxide to produce energy while releasing oxygen. Respiration is when humans and animals breathe in oxygen from the atmosphere to break the complex food molecules and breathe out carbon dioxide.

In the lithosphere, the weathering process occurs. We are not aware, but most oxygen is present in the mineral deposits, biomass, and organic content. Oxygen was deposited when certain metals were exposed to free oxygen to form oxides and silicates. The trapped oxygen gets released during weathering.

Let's find out its uses. All living organisms use oxygen for breathing, and we breathe in oxygen from the atmosphere, which reaches our cells and breathe out carbon dioxide.

Even in decomposition, oxygen is used. Decomposition plays an important part in the oxygen cycle and occurs in the death of an organism. The plants and animals decay in the soil, and the organic matter in the presence of oxygen, carbon, water, and other components is released to the soil and air. It is carried out by some bacteria and fungi known as decomposers.

Another important use of oxygen is in the combustion process. When things burn like fossil fuels, wood, and plastics, it is only possible in the presence of oxygen. Combustion releases carbon dioxide into the atmosphere. For fire, you need three things, heat, oxygen, and fuel. So combustion can occur when things burn.

Rusting is another process that also requires oxygen. Metals like iron rust when exposed to moisture and oxygen for a long time. The new oxides are formed because of the combination of metal and oxygen. The formation of these oxides is known as oxidation.

Continuous reactions of the radioactive elements

Interesting Facts About Oxygen Cycle For Kids

Life is possible only because of oxygen. The oxygen cycle mainly comprises plants that release oxygen and animals that breathe in oxygen from the atmosphere. Here are some fascinating facts about the oxygen cycle, which would help you know its importance and how it made life on earth possible.

Animals breathe in oxygen by the process of respiration. Even when plants and animals die, it is decomposed by using oxygen. Plants are responsible for creating the majority of the oxygen present in the atmosphere by the process known as photosynthesis. The oxygen in the atmosphere combines with carbon and hydrogen present in the wood to form carbon dioxide and water vapor, known as rapid oxidation.

About 65% of oxygen is present in the human body, and it is the most common element.

Fishes can pull out oxygen from the water molecules to breathe in the water. Phytoplanktons are tiny living creatures living on the ocean's surface, and even they provide us with much oxygen. 

Interestingly, the sun comprises 1 % of oxygen only.

A fire can only burn when oxygen, fuel, and heat are present.

On the surface of the Earth's crust, most oxygen is stored in minerals that are not available for use. If there are fewer plants and trees on Earth, there will be less oxygen supply. As we all know, plants are responsible for releasing oxygen. Let's keep our planet green and plant more trees.

Here at Kidadl, we have carefully created lots of interesting family-friendly facts for everyone to enjoy! If you liked our suggestions for everything about oxygen cycle for kids the vital element for all, then why not take a look at oxygen facts or do plants need oxygen to survive.

Written By
Sridevi Tolety

<p>With a Master's degree in clinical research from Manipal University and a PG Diploma in journalism from Bharatiya Vidya Bhavan, Sridevi has cultivated her passion for writing across various domains. She has authored a wide range of articles, blogs, travelogues, creative content, and short stories that have been published in leading magazines, newspapers, and websites. Sridevi is fluent in four languages and enjoys spending her spare time with loved ones. Her hobbies include reading, traveling, cooking, painting, and listening to music.</p>

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