We need this vital element to survive, but how much do actually you know about oxygen? Test your knowledge with these 20 fascinating and fun science facts.

  1. Oxygen is an element with the chemical symbol O and atomic number 8. Oxygen has 8 electrons and 8 protons.
  2. Oxygen is classified as a gas and nonmetal and is a member of the chalcogen group on the periodic table. It has an atomic weight of 15.999 and a density of 1.429g/L.
  3. At normal pressure and temperature, oxygen is composed of two oxygen atoms which join to form dioxygen (O2), a colourless, tasteless, odourless gas.
  4. Under standard conditions, oxygen is a gas at room temperature. It has a melting point of -218.79℃ and boiling point of -182.95℃.
  5. Oxygen is made of three stable isotopes: O-16, O-17, and O-18. O-18 is the most abundant isotope of oxygen, with an occurrence of  99.762%.
  6. Oxygen is a very reactive element that likes to bind with other elements and easily forms compounds such as oxides. However, the only two elements it does not form a compound with are helium and neon. The process of oxygen combining with other atoms to make compounds is called oxidation.
  7. Oxygen supports combustion and is required for fire, but itself does not burn and is not flammable.
  8. Liquid oxygen is pale blue in colour and magnetic.
  9. Oxygen dissolves in water. Fresh water contains about 6.04 mL of oxygen per litre, whereas seawater contains approximately 4.95 mL of oxygen per litre.
  10. Oxygen is essential to human life and is needed by most lifeforms on Earth to survive. Animals and plants require it for respiration. It is found in the air we breathe and the water we drink (as H2O).
  11. Oxygen makes up around 21% of the Earth’s atmosphere. It makes up around 50% of the Earth’s crust, making it the most common element in the Earth. Oxygen is also the third most abundant element in the universe and the most abundant element in the human body, making up 65% of the body’s mass. 1% of the Sun’s mass is oxygen.
  12. Oxygen plays an important role in life on Earth. This role is carried out through the oxygen cycle which is the movement of oxygen between air, living things, and the Earth’s crust.
  13. Oxygen found in the air is produced by photosynthesis - without plants there would be little oxygen in the air. Most oxygen on Earth comes from tiny ocean plants called phytoplankton.
  14. Oxygen also exists as the allotrope, ozone. Ozone O3 is a different form of oxygen that combines three oxygen atoms together to create trioxygen. Ozone O3 forms the ozone layer in the Earth’s upper atmosphere. It protects the Earth from the sun’s harmful rays by filtering UV light.
  15. Oxygen was discovered in 1771 by Swedish pharmacist Carl Wilhelm Scheele. However, he didn’t publish his results right away until after British chemist Joseph Priestley published his discovery of oxygen in 1774.
  16. The name oxygen was first used by French chemist Antoine Laurent Lavoisier in 1777 and comes from the Greek word oxygenes which means acid producer.
  17. Oxygen has many practical uses. It is most commonly used in the manufacture of steel. It is also used for smelting metal from ore, to filter water, for making plastic, and creating rocket fuel. Tanks of oxygen are also used to treat those with breathing problems and as life support for astronauts and scuba divers.
  18. Too much oxygen is however bad for us and causes a condition called the bends which is a particular problem for astronauts and scuba divers. This causes tiny bubbles in the blood which can be painful and sometimes deadly.
  19. 300 million years ago when oxygen levels were higher, insects grew bigger. Dragonflies were once as big as birds!
  20. The green colour of the aurora borealis, or northern lights, is caused by solar wind particles colliding with oxygen atoms in the earth’s atmosphere.

Want to learn more about oxygen, the elements, the periodic table, and chemistry? For more science, more amazing facts, and more fun, enrol now in our science holiday camp and spring term science classes where kids can learn, experiment, explore, and play!