Oxygen is a vital element that plays a crucial role in sustaining life on Earth. It is a colorless, odorless gas that makes up about 21% of the Earth’s atmosphere. In this article, we will explore some interesting facts about oxygen that you may not be aware of.

Did you know that oxygen is the third most abundant element in the universe? It is produced through various processes, including nuclear fusion in stars. On Earth, oxygen is primarily generated by plants during photosynthesis, where they convert carbon dioxide into oxygen.

Now, let’s dive into some of the most fascinating facts about oxygen.

Interesting Facts About Oxygen

These are the most intriguing facts about oxygen, not necessarily in the order:

Interesting facts About Oxygen

1. Oxygen makes up about 21% of Earth’s atmosphere.

Earth’s atmosphere is composed primarily of nitrogen (about 78%) and oxygen (about 21%), with small amounts of argon, carbon dioxide, and other trace gases. 

It’s this 21% of oxygen that is vital for the survival of aerobic organisms. When Earth first formed, it had little to no free oxygen. 

Over billions of years, the evolution of photosynthetic organisms increased the concentration of atmospheric oxygen, paving the way for the development of oxygen-breathing life.

2. Two atoms of oxygen make up an oxygen molecule, O2, but there’s also ozone, O3.

Most of the oxygen in the atmosphere is in the form of diatomic molecules (O2). However, there’s another form known as ozone (O3), which consists of three oxygen atoms. 

Ozone plays a crucial role in the Earth’s stratosphere by absorbing the majority of the Sun’s harmful ultraviolet radiation, hence protecting life on Earth from its detrimental effects.

3. Liquid and solid oxygen are pale blue.

While oxygen gas is colorless and odorless, when it’s in its liquid or solid state, it has a pale blue color. 

This is due to the absorption of light in the red part of the visible spectrum, which results in the blue hue. Liquid oxygen is used in some rocket propulsion systems and is extremely reactive.

4. Oxygen is the third most abundant element in the universe by mass.

After hydrogen and helium, oxygen is the most abundant element found in the universe. 

It plays a pivotal role in the life cycle of stars and is a primary component of water (H2O), making it essential for the possibility of life as we understand it on other planets.

5. Humans can’t breathe 100% pure oxygen for extended periods.

While oxygen is essential for our survival, breathing 100% pure oxygen for extended periods can be harmful. 

It can lead to oxygen toxicity, which affects the central nervous system and the lungs. In environments like hospitals, patients are sometimes given high concentrations of oxygen, but it’s carefully monitored to avoid any harmful effects.

6. The name “oxygen” comes from the Greek words “oxy” and “genes,” meaning “acid-forming.”

Oxygen was named by Antoine Lavoisier. He believed that oxygen was a necessary component for forming all acids, hence the name derived from the Greek words. 

Although this belief was later proven incorrect (as there are acids without oxygen, like hydrochloric acid), the name stuck.

7. Without oxygen, the Earth’s oceans would evaporate.

Oxygen plays a vital role in the Earth’s water cycle. Water (H2O) is made up of hydrogen and oxygen. Without oxygen, water wouldn’t exist, and the oceans would evaporate. 

The presence of liquid water on Earth is one of the primary reasons our planet can support life.

8. Oxygen supports combustion, but it doesn’t burn.

While oxygen itself is not flammable, it supports the combustion of other materials. In an environment rich in oxygen, things burn much more readily and energetically than they would in normal air. 

This is why oxygen tanks are handled with extreme caution around open flames or sparks.

9. Over half of the Earth’s crust is made of oxygen.

When we think of the Earth’s crust, images of rocks and minerals come to mind. 

But by weight, more than half of the crust is composed of oxygen, mainly because it combines with silicon to form silicate minerals. These minerals make up the majority of the Earth’s crust.

10. Oxygen therapy can help treat several conditions.

Oxygen therapy, where a person breathes in extra oxygen, is used to treat a variety of medical conditions. 

This includes chronic obstructive pulmonary disease (COPD), pneumonia, some heart disorders, and any condition that results in decreasing the amount of oxygen in the blood to below normal levels.

11. Hyperbaric oxygen therapy is used to treat decompression sickness.

Hyperbaric oxygen therapy involves breathing pure oxygen in a pressurized room or chamber. It’s a well-known treatment for decompression sickness, a hazard of scuba diving. 

The increased pressure allows more oxygen to reach the body’s tissues and aids in healing.

12. The discovery of oxygen is credited to multiple scientists.

The discovery of oxygen is a subject of debate because it was identified independently by several scientists. 

Carl Wilhelm Scheele in Sweden, Joseph Priestley in England, and Antoine Lavoisier in France are the key figures associated with its discovery. 

Although Scheele and Priestley discovered it earlier, Lavoisier is often credited due to his comprehensive studies and for naming the element.

13. Our moon has extremely thin traces of oxygen.

While the moon’s atmosphere is nearly nonexistent and often referred to as an exosphere, it does contain extremely thin traces of various gases, including oxygen. 

However, these amounts are so minuscule that they aren’t useful for human breathing.

14. Plants produce oxygen through photosynthesis.

One of the vital processes for life on Earth, photosynthesis, is carried out by plants, algae, and certain bacteria. 

They take in carbon dioxide and release oxygen, providing the necessary balance of gases in our atmosphere and making Earth habitable for oxygen-dependent creatures.

15. Oxygen has isotopes that are used in medical and research applications.

While O-16 is the most abundant isotope of oxygen, there are stable isotopes like O-17 and O-18 that have been used in various research applications. 

Oxygen isotopes are crucial in paleoclimatology to trace changes in ancient climates.

16. Oxygen can exist in several allotropic forms.

In addition to the common diatomic molecule (O2) and ozone (O3), there are allotropes of oxygen like tetraoxygen (O4) detected in specific high-pressure conditions. These are not stable under typical conditions on Earth but are of interest in the fields of chemistry and astrophysics.

17. The Earth’s early atmosphere had very little free oxygen.

Billions of years ago, the Earth’s atmosphere lacked significant amounts of free oxygen. The oxygen-rich atmosphere we have today is the result of photosynthetic cyanobacteria, which began producing oxygen around 2.4 to 3 billion years ago, a period known as the Great Oxygenation Event.

18. Oxygen bars became trendy in the late 1990s and early 2000s.

An “oxygen bar” is a place where pure oxygen is sold to be inhaled. Originating in Japan in the 1990s, these bars became a trend in many parts of the world, offering flavored oxygen for recreational inhalation. 

While many claims were made about the benefits of inhaling pure oxygen in this manner, there’s limited scientific evidence to support most of them.

19. Molecular oxygen (O2) is paramagnetic.

While most substances are not magnetic, molecular oxygen exhibits a form of magnetism called paramagnetism. 

This is due to the presence of two unpaired electrons in its molecular structure. It’s a unique characteristic and can be demonstrated by suspending liquid oxygen between the poles of a powerful magnet.

20. In the medical field, “oxygen saturation” is a crucial metric.

Oxygen saturation refers to the fraction of oxygen-saturated hemoglobin relative to total hemoglobin in the blood. 

A healthy individual typically has an oxygen saturation of 95-100%. Monitoring oxygen saturation is vital, especially in critically ill patients, to ensure they’re receiving adequate oxygen.

21. The majority of the Earth’s oxygen is produced by the oceans.

While forests are often dubbed the “lungs of the Earth,” the majority of our planet’s oxygen is produced by tiny marine plants called phytoplankton. 

These microscopic organisms live near the surface of the water and generate oxygen through photosynthesis.

22. Oxygen is used in welding and metal cutting.

Because of its reactive nature, oxygen is used in oxy-fuel welding and cutting. When combined with a fuel gas, it produces a flame hot enough to melt and even vaporize metals. 

This process is commonly used in various industries and construction.

23. Breathing high concentrations of oxygen under pressure can lead to “oxygen toxicity.”

Breathing oxygen at high pressures, such as in deep-sea diving, can result in oxygen toxicity. This can affect the central nervous system and cause symptoms like nausea, twitching, and even seizures.

24. Apollo 1 tragedy was related to pure oxygen.

One of the tragic events in space exploration, the Apollo 1 accident, where three astronauts lost their lives during a pre-launch test, was due to a fire in an environment of pure oxygen. The fire spread rapidly, leading to a catastrophic outcome.

Fun Facts About Oxygen for Students

Here are some of the coolest fun facts about oxygen for students and kids:

Fun facts about oxygen

1. Earth’s air is like a big breath of oxygen.

When you take a deep breath, a lot of what you’re breathing in is oxygen! In fact, about 1 out of every 5 breaths you take is pure oxygen. That’s because oxygen makes up 21% of the air around us.

2. Oxygen has a cool cousin named ozone.

Oxygen usually hangs out in pairs, which we call O2. But sometimes, it likes to form a trio, which is known as ozone or O3. Ozone is super cool because it acts like Earth’s sunglasses, blocking harmful sun rays up high in the sky.

3. Liquid oxygen is blue like the sky.

We can’t see oxygen when we breathe it in. But if you chill oxygen until it becomes liquid, it turns a light blue color. It’s almost as if you have a piece of the sky in a bottle!

4. Oxygen loves to be in a group.

Oxygen is very friendly! It likes to bond or “hold hands” with lots of other elements. When it bonds with hydrogen, they create water. That means every time you drink a glass of water, you’re having some oxygen too!

5. Fires need oxygen to keep burning.

Have you ever seen a candle flame go out when you put a glass over it? That’s because the flame uses up all the oxygen inside the glass, and without more oxygen, it can’t keep burning. Remember, fire and oxygen are best buddies, so we should always be careful around open flames.

6. Plants are like tiny oxygen factories.

Every time plants soak up sunlight, they take in carbon dioxide and give out oxygen. This process is called photosynthesis. So, the next time you see a tree or a plant, give it a little ‘thank you’ for the fresh oxygen!

7. Too much of a good thing can be bad.

While our bodies love oxygen, breathing in pure oxygen for a long time isn’t good for us. It’s like eating too much candy; a little is sweet, but too much can give you a tummy ache!

8. You can find oxygen all over the place!

Oxygen isn’t just in the air. It’s also in rocks, metals, and even in your school pencils! When oxygen joins with carbon, they create a material called graphite, which is what the “lead” in your pencil is made of.

9. Astronauts take oxygen to space.

Space doesn’t have air like Earth does. So, astronauts have to carry their supply of oxygen when they go on space missions. Imagine packing an oxygen bag for a space trip!

10. Our name for oxygen comes from a language super old!

The word “oxygen” comes from two ancient Greek words: “oxy,” meaning sharp, and “genes,” meaning born of. It got this name because scientists once thought all acids had oxygen in them.

Most Common Uses of Oxygen

1. Medical Applications

Oxygen is widely used in medical applications to support patients with respiratory conditions or those in need of supplemental oxygen. 

It is commonly administered through oxygen masks or nasal cannulas to increase the oxygen levels in the blood, aiding in the treatment of various respiratory disorders such as asthma, chronic obstructive pulmonary disease (COPD), and pneumonia.

2. Industrial Processes

Oxygen plays a crucial role in various industrial processes, including combustion, oxidation reactions, and metal cutting. It is used in the production of steel, chemicals, and glass. 

Additionally, oxygen is employed in wastewater treatment plants to enhance the efficiency of biological processes that break down organic matter.

3. Aerospace and Aviation

Oxygen is essential for human survival at high altitudes where the air is thin and lacks sufficient oxygen. 

In aerospace and aviation industries, oxygen is used in aircraft cabins and spacesuits to provide breathable air for pilots, crew members, and passengers during flights or space missions.

4. Aquaculture

Oxygen is crucial in aquaculture, the farming of aquatic organisms such as fish, shrimp, and oysters. It is used to maintain adequate oxygen levels in fish tanks or ponds, ensuring the survival and growth of aquatic species. 

Oxygen supplementation helps prevent oxygen depletion and promotes healthier aquatic environments.

5. Oxy-fuel Welding and Cutting

Oxygen is a key component in oxy-fuel welding and cutting processes. When combined with a fuel gas such as acetylene, oxygen supports high-temperature combustion, enabling efficient metal cutting, welding, and brazing operations in industries like construction, automotive, and manufacturing.

6. Scuba Diving

Oxygen is vital for scuba divers to breathe underwater. It is used in scuba diving equipment, such as diving cylinders or tanks, to provide a supply of breathable air at various depths. 

The oxygen mixture is carefully regulated to ensure diver safety and prevent decompression sickness.

7. Laboratory Experiments

Oxygen is extensively used in laboratory experiments and research. It serves as a reactant in chemical reactions, supports combustion experiments, and provides an oxidizing environment for various analytical techniques. Oxygen gas cylinders are commonly found in laboratories for these purposes.

Chemistry of Oxygen


The discovery of oxygen can be attributed to several scientists who made significant contributions to its understanding. 

In the late 17th century, Robert Boyle conducted experiments on the behavior of gases and observed that a substance, which he called “”spiritus nitroaereus,”” was necessary for combustion to occur. This substance was later identified as oxygen. 

In the 18th century, Joseph Priestley and Carl Wilhelm Scheele independently isolated oxygen gas by heating various compounds. 

However, it was Antoine Lavoisier who provided the most comprehensive understanding of oxygen’s role in chemical reactions and named it “”oxygen”” in 1777.


Oxygen has a rich history that spans centuries. The ancient Greeks believed that air was one of the four fundamental elements, along with earth, fire, and water. 

However, it wasn’t until the 18th century that oxygen was recognized as a distinct element. Lavoisier’s experiments on combustion and respiration led to the understanding that oxygen was essential for these processes. 

This discovery revolutionized the field of chemistry and laid the foundation for the study of chemical reactions and the concept of oxidation.

Basic Chemistry

Oxygen is a chemical element with the symbol O and atomic number 8. It is a highly reactive nonmetal that readily forms compounds with other elements. In its pure form, oxygen exists as a diatomic molecule (O2), which makes up approximately 21% of Earth’s atmosphere. 

Oxygen is essential for the survival of most living organisms, as it is involved in cellular respiration, the process by which energy is produced. It also plays a crucial role in combustion reactions, supporting the burning of fuels. 

Oxygen has a strong affinity for electrons, making it a powerful oxidizing agent. It readily reacts with other elements, such as hydrogen, carbon, and metals, to form oxides. For example, when oxygen reacts with hydrogen, it forms water (H2O). 

This reaction is fundamental to the production of energy in living organisms. Additionally, oxygen is a key component in the formation of ozone (O3) in the Earth’s ozone layer, which protects us from harmful ultraviolet radiation. 

Interesting Physical Properties of Oxygen

1. Colorless and Odorless

Oxygen is a colorless and odorless gas, which means it cannot be seen or smelled by humans. 

This property makes it difficult to detect its presence in the air without the use of specialized equipment. Despite being invisible, oxygen is essential for supporting life and is a vital component of the Earth’s atmosphere.

2. High Boiling and Melting Points

Oxygen has a high boiling point of -183 degrees Celsius (-297 degrees Fahrenheit) and a melting point of -218.79 degrees Celsius (-361.82 degrees Fahrenheit). 

These high temperatures are due to the strong intermolecular forces between oxygen molecules, which require a significant amount of energy to break apart and change its state from a gas to a liquid or solid.

3. Paramagnetic Nature

Oxygen is paramagnetic, meaning it is weakly attracted to magnetic fields. This property arises from the presence of unpaired electrons in its atomic or molecular orbitals. 

When exposed to a magnetic field, oxygen molecules align themselves with the field, exhibiting a slight attraction. This property has various applications in industries such as medicine, electronics, and chemistry.

4. Supports Combustion

Oxygen is a highly reactive gas that readily supports combustion. It acts as a vital component in the process of burning, allowing substances to react with it and release energy in the form of heat and light. 

This property is why oxygen is necessary for sustaining fire and is often used in industrial processes such as welding and metal cutting.

5. Low Density

Oxygen has a relatively low density compared to many other gases. Its density is approximately 1.43 grams per liter at standard temperature and pressure. 

This property makes oxygen lighter than air, allowing it to rise and disperse in the atmosphere. The low density of oxygen also contributes to its ability to support life, as it can be easily inhaled and transported by the respiratory system.