--- title: "Elephant toothpaste experiment for kids, done safely" description: "Elephant toothpaste for kids: the safe home version with 3% hydrogen peroxide, yeast and dish soap, poured by an adult. Steps, safety and why it foams." source_name: "Game Tailors" source_url: "https://extreemtekenen.nl/en/experiments/elephant-toothpaste/" site_home: "https://extreemtekenen.nl/" source_description: "The drawing app where the paper is real. No ads, no accounts, no data collected." locale: "en" legal: - "Game Tailors · Schieweg 15Y-40, 2627 AN Delft (NL)" - "KvK 92437702 · VAT NL866044474B01" - "info@gametailors.com · +31 6 4227 5919" copyright: "© 2026 Game Tailors" published_at: "2026-10-22T18:52:25.276Z" modified_at: "2026-10-24T01:17:23.571Z" --- # Elephant toothpaste experiment for kids, done safely ## A warm snake of foam that keeps on coming Elephant toothpaste is a bottle that pours out a fat column of foam. Yeast makes hydrogen peroxide break down into water and oxygen very fast, dish soap traps the oxygen in bubbles, and the reaction gives off heat, so the foam is warm. [Play in your browser]()[Do it for real](<#for-real>) - Ages 5\+ - 15 minutes - An adult pours ![Painted illustration of a bottle on a tray pouring out a fat foam snake in pink, yellow, blue and white stripes, the painter in goggles leaning back, amazed.]() ## Quick facts Age 5 to 10 \(children mix the yeast, an adult handles the peroxide\) Time 15 minutes, plus 5 to clean up Mess Medium: foam on a tray Adult needed Yes, and goggles for everyone close by You need 3% hydrogen peroxide, dry yeast, dish soap, a bottle \(a few euros or dollars\) On screen / for real Both \(for real: only the 3% household version\) ## Elephant toothpaste in Extreme Drawing Open the **Science** tab \(free\), tap **Eruptions** and choose **Elephant toothpaste**. Then tap the paper where the bottle should stand. For about four and a half seconds a fat, stripy snake of foam \(pink, yellow, blue and white\) pushes out of the bottle mouth. It wobbles off in a random direction and piles up with bubbles. The spot under the bottle gets **warm**, just as a real bottle does. The foam behaves like foam: it runs and spreads, then slowly collapses and leaves its stripes behind as stains in the paper. Tilt the page \(or paint at the easel\) and it slides downhill. Pat it with the hand, the hammer or the iron and the bubbles pop. No goggles, no peroxide, no clean-up: set off as many bottles as you like, then do it once for real. [Play in your browser]() ![Painted illustration of the painter, goggles on his beret, studying a bottle foaming over in stripes, with red cabbage juice in pink and green glasses and fizzing baking soda.]() ## The safe home version **You need** - 120 ml \(half a cup\) of **3% hydrogen peroxide**, the household strength sold in pharmacies and supermarkets. Never anything stronger. - 1 tablespoon \(one sachet\) of dry yeast - 3 tablespoons of warm water - 1 tablespoon of dish soap \(washing-up liquid\) - A few drops of food colouring \(optional\) - A clean 500 ml plastic bottle and a funnel - A tray or a deep baking dish to catch the foam - Safety goggles for everyone close by, and gloves for the adult The grown-up pours the peroxide. The children mix the yeast, add the colour and do the predicting. 1. Set up on a trayStand the bottle in the tray, outside or on a wipeable kitchen surface. Goggles on for everyone. 2. The adult adds the peroxideWith the funnel, the adult pours the hydrogen peroxide into the bottle, then the dish soap. A child can add a few drops of food colouring and the adult swirls it gently. 3. Wake up the yeastIn a small cup, the child stirs the yeast into the warm water for about 30 seconds until it's a smooth, runny paste. This is the safe job for small hands. 4. PredictHow tall will the foam get? Will it be hot or cold? Draw a line on a piece of card to mark your guess. 5. Pour and step backThe adult pours the yeast paste into the bottle through the funnel, pulls the funnel away and everyone takes a step back. 6. Watch, then feel the warmthThe foam pushes out for a minute or so. When it has stopped, the adult can let children hold a hand near the bottle to feel that it's warm. 7. Clean upThe adult rinses the foam and what's left in the bottle down the sink with plenty of water. Everyone washes their hands. Safety: read this first - **Only 3% household hydrogen peroxide.** Never hair-salon developer or any stronger peroxide: the big school-lab demonstrations use much stronger peroxide that can burn skin, and that version is for trained adults only. - **Children don't touch the peroxide.** It stings eyes and skin. If any splashes in an eye, rinse with running water for 15 minutes and call your poison centre \(in the US, Poison Control on 1-800-222-1222\). - **The foam is warm.** Look first; don't touch it until the adult says so, and wash hands afterwards. - **It isn't toothpaste.** Nothing goes in mouths. Keep the peroxide bottle closed and out of reach. ### For kids The peroxide is full of oxygen that wants to get out. The yeast helps it escape all at once, and the soap catches it in bubbles, so out comes a giant warm snake of foam. ## Why it foams \(and why it gets warm\) **For grown-ups.** Hydrogen peroxide \(H₂O₂\) slowly breaks down into water and oxygen on its own: 2 H₂O₂ → 2 H₂O \+ O₂. Yeast contains an enzyme, catalase, that speeds this up enormously. It's a **catalyst**: it makes the reaction go faster without being used up. The dish soap catches the sudden rush of oxygen in millions of bubbles, so the gas comes out as foam instead of escaping into the air. Breaking down peroxide releases energy as heat, so it's an **exothermic** reaction, and you can feel it in the bottle. With 3% peroxide the foam is warm, not hot. The oxygen gas is a new substance that wasn't in the bottle before, and the change can't be undone: that's how you know it's a chemical change. ## Predict, then try next Change one thing at a time and make a guess before you pour. ### No soap? Leave the soap out. You'll see fizzing but hardly any foam. Where did the oxygen go? ### Cold water for the yeast? Mix the yeast with cold water instead of warm. Does the foam come slower? ### A wide jar or a narrow bottle? The same amounts in a jam jar. Does a narrow neck make a taller snake? ### What does cabbage juice say? In the app, dip the paper in red cabbage juice \(Time tab\) before the eruption. The foam reads as slightly alkaline, so it turns the purple a little bluer. ## Elephant toothpaste in the classroom A new gas, heat and no going back: it fits KS2 Year 5 *properties and changes of materials* \(irreversible changes that make new materials\) and NGSS 5-PS1-4 \(mixing substances can make a new substance\). For older pupils it introduces catalysts and exothermic reactions \(KS3 chemistry, NGSS MS-PS1-2\). Show the app version on the whiteboard first, so the whole class sees it up close, then do one bottle as a teacher demonstration with goggles. [Ideas for teachers]() ## Elephant toothpaste questions Is elephant toothpaste safe for kids? The home version is safe when an adult handles the 3% hydrogen peroxide, everyone wears goggles and nobody touches the foam until the adult says so. Children can safely mix the yeast and add the colour. Never use stronger peroxide. Can you make elephant toothpaste without hydrogen peroxide? Not the real reaction: the peroxide is where the oxygen comes from. For a peroxide-free foam, add dish soap to baking soda and vinegar. It foams up too, with carbon dioxide instead of oxygen, and it doesn't get warm. Why does elephant toothpaste get warm? Breaking hydrogen peroxide down into water and oxygen releases energy as heat. That makes it an exothermic reaction. With household 3% peroxide the foam and bottle feel warm, not hot. Why is it called elephant toothpaste? Because the thick foam squeezing out of the bottle looks like toothpaste coming out of a tube big enough for an elephant. What can you do with the foam afterwards? Let the adult rinse it down the sink with plenty of water. It's mostly water, soap, yeast and oxygen bubbles, but there can be a little peroxide left in it, so it isn't for playing with or tasting. ## More fizz and foam ![Painted illustration of the painter pouring red vinegar onto a heap of baking soda on a tray, which fizzes up into pink foam.]() ### [Baking soda and vinegar]() The classic volcano: coloured foam that fizzes up wherever an acid meets the powder. ![Painted illustration of a cola bottle on the grass shooting up a tall fountain of foam as mints drop in, the painter in goggles laughing beside it.]() ### [Mentos and coke]() A fountain of cola that isn't a chemical reaction at all. ![Painted illustration of the painter putting a closed bleach bottle away on a high shelf, the vinegar kept on another shelf, beside an open window.]() ### [Kitchen safety]() What stays on the screen only, and why: bleach and vinegar, fire, the grease fire. ## Set off a bottle on screen Science tab, Eruptions, Elephant toothpaste: tap and watch the stripes pour out. Then find a grown-up and some goggles. [Play in your browser]()[All experiments]()