whoa g'day science fans and welcome back to another episode of scitec at home my name is mita and today i'm going to be making some elephants toothpaste what's that you say this isn't a dental hygiene program for large mammals you're right it's not elephant's toothpaste is actually just a fun name that we give for a reaction involving the decomposition of hydrogen peroxide in the presence of dish soap that was a lot of words let's break that down a bit and talk about what i really mean and this is what the decomposition of hydrogen peroxide looks like h2o2 and it breaks down to water h2o and oxygen what does this reaction look like in real life let's find out now even though hydrogen peroxide hangs around in our supermarkets and in our chemists at high concentrations that means when there's a lot of it in a solution it can actually be quite toxic to human skin and it can cause some burns so i'm going to use some protective equipment safety glasses [Music] and gloves so in my cylinders i've got two solutions of hydrogen peroxide one of them six percent quite weak one of them thirty-five percent quite strong and because i like to make things pretty i'm gonna add a little bit of food coloring blue the weak stuff and red for the strong stuff [Music] first of all i'm gonna add some regular dish soap and the reason i'm adding this is because this reaction is forming a gas which is oxygen now what happens when you put gas water and dish soap together you get bubbles now in these two test tubes i've got something called potassium iodide this is something that we call a catalyst now a catalyst is a very special thing in chemistry that makes a reaction go faster it doesn't actually react with anything in the mixture itself it makes it easier for the reaction to occur now what do you think will happen when i put my catalyst or my reaction speeder upper in my weak solution of hydrogen peroxide make your predictions and let's try it out [Music] inside this graduated cylinder now we have a sped up decomposition reaction and the gas is mixing with the detergent in the presence of water and creating bubbles and you can see that those bubbles are rising much much quicker now that we've got the catalyst in there do you think it's going to get to the top i think it might but over here on the left we have a stronger solution and i think we can have a bit of a race what do you think is going to happen when i add the catalyst to our stronger solution do you think it's going to go faster should we try it out in three two one whoa now that strong concentration meant that there was so much more hydrogen peroxide in that solution and so what we've had here is a much bigger reaction and that's why it's called elephant's toothpaste so let's talk about how you can do this at home now here i've got an old container of dishwashing liquid which had almost run out there was just a little bit of the dish soap in there if there isn't any dish soap you can just add some more and i've also got some of the weak concentration of hydrogen peroxide so i use the six percent but you could try this with the stuff that you get from your supermarket or from your chemist it's probably gonna be around three percent and instead of using potassium iodide as a catalyst i brought along some of my friends inside this beaker i have some yeast now yeast you can just buy the supermarket yeast is actually a living organism and that's what makes it a great catalyst for this reaction so most living organisms inside their tissue is something called catalase which will help catalyze the reaction in the same way that the potassium iodide did so to do this reaction i'm going to take the lid off my container i'm going to leave it there because we're going to put that on again in a moment and i'm just going to wake our yeast up with a little bit of warm water from the tap let's give that a bit of a stir make sure that all of that yeast is going to make it into our vessel now you've already seen this reaction done before so make your predictions what do you think is going to happen when i add the yeast into the container of hydrogen peroxide and dishwashing detergent have you made your prediction all right let's try it out i'm going to use a funnel this time to keep the mess down just a little bit and we're going to add this in five four three two one all right you can see those bubbles are rising am i gonna get the lid on on time probably not blow the lid right off whoa and what you have here is a super fast elephant's toothpaste reaction done with stuff that you've got around the house so thanks for playing along see you next time