• Question: How do you make the elephant toothpaste chemical reaction

    Asked by anon-254198 to James_the_Scientist on 14 May 2020.
    • Photo: James Beswick

      James Beswick answered on 14 May 2020:

      This is definitely one of the most popular demonstrations in chemistry! The reaction behind this foamy mess is the decomposition of a chemical called hydrogen peroxide (which has bleaching and antiseptic properties) into water and oxygen, with heat also given off – which is why the foam produced is hot. Hydrogen peroxide does decompose on its own, but very slowly. The elephant’s toothpaste demonstration makes use a of a catalyst (which increases the rate of a chemical reaction) called potassium iodide – which makes for a very quick reaction. Washing up liquid is also added to give the ‘foam’ which is made from the water and oxygen produced by the reaction. Like any chemical reactions, this one can be dangerous if not done properly with appropriate safety equipment.

Comments

  • Photo: Leanne

    Leanne commented on :

    I love that experiment! It’s so messy and fun! And if you add food colouring to the liquid, you can race to see which colour is fastest to make the foam.

    If you want to try it at home, it also works (although not as fast) if you use dried yeast – it works as a biological catalyst! It still reacts with very dilute hydrogen peroxide to make water and oxygen, and makes excellent foam if you add washing up liquid! Just be careful, even dilute hydrogen peroxide is a chemical that should be handled with care (and gloves), and with the help of an adult!