Oxygen is an element found as a gas at room temperature. It makes up 21% of the composition of the atmosphere. The discovery of this element gave us a better understanding of chemical reactions, specifically combustion and respiration. Respiration is a chemical reaction which is essential for life.
Oxygen is the 8th element on the periodic table. It makes up 21% of the Earth’s atmosphere and is essential to life. It is normally found as a diatomic molecule, which is a colorless, odorless gas, but can also be found as O3, known as ozone. Half of the Earth’s atmosphere is made of compounds which contain oxygen.
The ozone layer is a layer around the Earth that is made up of high concentrations of ozone. This layer absorbs large amounts of the Sun’s UV rays before they reach the surface. This UV light would be very harmful to life on Earth we weren’t shielded by the atmosphere.
Respiration is a chemical reaction all living things use to release energy from nutrients. Inside cells, oxygen reacts with glucose to produce carbon dioxide and water (C6H12O6 + 6O2 → 6CO2 + 6H2O) This is an essential reaction for life on Earth. Oxygen is also a product of the chemical reaction plants use to create food, photosynthesis.
As well as biological reactions, Oxygen is also essential for combustion. Combustion, also known as burning, has been used for thousands of years to provide heat to humans. Combustion of fossil fuels is used for transportation. Oxygen is also used in medicine to treat people who have breathing difficulties, and recreationally for divers and submariners.
Cornelius Drebbel found that when heating potassium nitrate a gas was released, but he didn’t identify it as oxygen. The Swedish chemist Carl Wilhelm Scheele and British clergyman Joseph Priestley are both credited with discovering oxygen.
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How to create a hands-on oxygen cycle demonstration for your classroom
Engage students by showing them how oxygen moves through the environment with a simple, interactive activity. This demonstration helps students visualize the oxygen cycle and understand its importance for plants, animals, and humans.
Gather simple materials for your demonstration
Collect clear jars, water, leafy plants (like spinach or elodea), drinking straws, and small aquatic animals (like snails or goldfish, optional). Label each jar to keep track of their contents. Having materials ready helps the activity run smoothly.
Set up the plant and animal jars to model oxygen exchange
Place a plant in one jar filled with water, and an animal in another. Explain that the plant produces oxygen during photosynthesis, while the animal uses oxygen for respiration. Discuss what might happen to each jar over time.
Demonstrate oxygen movement with bubbles
Let students use straws to gently blow bubbles into a third jar of water to add oxygen, mimicking natural processes. Observe how bubbles rise and talk about how oxygen enters water in lakes and rivers. Connect this to real-life ecosystems.
Discuss observations and connect to the oxygen cycle
Ask students what they notice in each jar after a day or two. Guide a discussion about how plants and animals depend on each other for oxygen and carbon dioxide. Highlight the cyclical nature of oxygen in our environment.
Frequently Asked Questions about What is Oxygen?
What is oxygen and why is it important?
Oxygen is a colorless, odorless gas that is essential for life. It helps living things breathe and is key to many chemical processes, including burning and rusting.
How do humans and animals use oxygen?
Humans and animals inhale oxygen from the air, which their bodies use to make energy from food. This process is called respiration and is vital for survival.
Where can oxygen be found in nature?
Oxygen is found in the air (about 21%), in water as part of the H2O molecule, and in many rocks and minerals.
What are some fun facts about oxygen?
Oxygen makes up nearly one-fifth of Earth’s atmosphere, helps fire burn, and is the most abundant element in the human body by mass.
How is oxygen used in schools and classrooms?
Oxygen is often discussed in science classes to teach about the air we breathe, chemical reactions, and the needs of living things.
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