The Sound of Science - "How is Oxygen Made?"

Feb 15, 2019

Sam: Welcome to the Sound of Science, I’m Sam from NIU STEM Outreach.

Jeremy: And I’m Jeremy! This week’s question comes from Hazel in Dekalb.

Hazel: I want to know how oxygen is made?

Sam: That’s a pretty good question. Jeremy, where does the oxygen we breathe come from?

NIU STEM Outreach

Jeremy: We can thank all the plants and trees in the world for that! They take in the carbon dioxide we breathe out, use the carbon, and release oxygen molecules. But that doesn’t really explain how the oxygen even came to exist! For that, we need to think about nuclear fusion.

Sam:  In nuclear fusion, two smaller elements combine to create a heavier element.  The new element, while heavier, still weighs a bit less than the sum of the original elements did.  That extra mass is transformed and given off as energy.

Jeremy:  This is how the stars produce energy.  Our sun combines very light elements like Hydrogen into heavier elements like Helium.  In the process, each individual reaction changes a tiny bit of mass into pure energy.

Sam: Wait…this sounds really familiar…

Jeremy: Yeah we brought it up when we talked about E=mc2and energy!

Sam: Well Hazel, it’s the same process, but over a much longer time. If you look at a periodic table of elements, you’ll see 118 unique elements. However, less than 100 are found naturally. Those 100-ish all started out as little hydrogens undergoing fusion to form helium, then the helium atoms fusing into larger and larger elements like beryllium and carbon. This includes that sweet, sweet oxygen!

Jeremy: The star continues combining atoms for millions of years, but eventually it will begin to die out. When the star has used up most of its usable fuel, it’ll collapse in on itself and explode! You’ve probably heard this described as a supernova.

Sam: The supernova scatters itself and all the elements into the galaxy. Stars are so big and have so many atoms that the remnants go on to form planets -- Maybe even a planet that might one day support life!

Jeremy: Every atom of carbon in your body and every atom of oxygen you breathe started in the hearts of stars. So each time you take a deep breath, you can thank ancient stars for creating the oxygen.

Sam: Great question Hazel! Keep your questions coming by emailing us at This has been the Sound of Science on WNIJ

Jeremy: Where you learn something new everyday.