• Question: how do plants produse oxygen

    Asked by anon-359330 on 18 Mar 2023.
    • Photo: Alexandra Milliken

      Alexandra Milliken answered on 18 Mar 2023:

      Plants need three main ingredients: sunlight, carbon dioxide (CO2) and water (H2O). They obtain water from the soil through their roots. CO2 is taken in from the atmosphere via stomata (small holes) on a plant leaf. Plants then use the energy from sunlight to convert CO2 and H2O into a sugar (glucose; C6H12O6) and O2 (oxygen). Oxygen is a by-product of this reaction and is released from the leaf into the air via stomata.

      You can do a small experiment to view Oxygen production from a leaf. Take a leaf (carefully) from a plant and put it in a glass of cold water (make sure the leaf is fully underwater). After leaving the glass in the sun for around an hour, you should be able to see a lot of bubbles (Oxygen).

    • Photo: Sam Mugford

      Sam Mugford answered on 19 Mar 2023:

      Alexandra gives a great answer. The oxygen released by the plants comes from the water molecules. The splitting of water into the oxygen and hydrogen that makes it up is a crucial part of photosynthesis. It takes a lot of energy to split a water molecule. You can do it with electricity- if you stick some electrodes in a glass of water and put a hefty voltage across it you will see bubbles forming at both electrodes, hydrogen bubbles at the cathode and oxygen bubbles at the anode. This is how oxygen is made on a nuclear submarine, using the energy from a nuclear reactor.

      Plants also use the energy from a nuclear reactor to make oxygen, because the sun is a pretty big nuclear reactor, and plants use the energy it releases (sunlight) to split water into oxygen and hydrogen.

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