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NESA Accredited Teacher
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High school chemistry & physics specialist 30+ years
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The Crazy Scientist in primary schools — 15 years
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International conference presenter on science education
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Creator of the LAB™ Learning System
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Curriculum aligned: NSW Science & Technology K–6 (2024)
A picture is worth a thousand words — check this out and see if you can spot the science hiding in plain sight.
From the LAB
What you will need
• 1 empty plastic bottle — a 600mL
• 120mL (½ cup) hydrogen peroxide — 3%
• 1 tablespoon dry yeast
• 3 tablespoons warm water — warm, not hot
• 1 large squirt of dish soap — about 1 tablespoon
• Food colouring — optional, for coloured foam
• A measuring cup and spoons
• A large tray or baking dish — to catch the foam
• Safety glasses — hydrogen peroxide can irritate eyes; everyone present wears them
• For Variable 2: a raw potato — grated finely
How to do it
1
Make your prediction
Before you touch anything, write down your theory.
You have three ingredients: hydrogen peroxide, dish soap, and dry yeast. What do you think each one is doing?
3
Wake up the yeast
In your measuring cup, mix 1 tablespoon of dry yeast with 3 tablespoons of warm water.
Stir for about 30 seconds. The yeast is now active — you might see it starting to look a little frothy.
This is the escape artist getting ready.
5
Check your prediction
Go back to what you wrote in Step 1.
Was your theory right? What was the yeast actually doing — was it adding something, removing something, or speeding something up?
Write one sentence that corrects or confirms your original prediction.
2
Prepare the bottle
Pour 120mL (½ cup) of hydrogen peroxide into the bottle.
Add a large squirt of dish soap and swirl very gently to mix — do not shake.
If you want coloured foam, add a few drops of food colouring now and swirl gently.
4
Start the reaction
Pour the yeast mixture into the bottle and step back immediately.
Do not put your face over the bottle. Watch what happens. Record: how fast does it start?
How long does it keep going? When it slows down, carefully touch the outside of the bottle. What do you notice about the temperature?
Did it work? Share the science! Tag @the_crazy_scientist on Instagram — we love seeing your experiments!
The Escape Artist
Designed by Darin Carr (BSc, DipEd)
NESA Accredited Teacher Chemistry & Physics Specialist
Creator of the LAB™ Learning System
Inside every bottle of hydrogen peroxide, something is trying to escape. Normally it takes weeks. A tiny packet of dry yeast is about to make it happen in seconds — and you will not be able to stop it.
5-12 yrs
Easy
20
min
Stage 3
>
The Escape Artist
The Crazy Scientist LAB Learning System™
Every experiment follows The Crazy Scientist Lab Learning System™ — a simple way to help kids think like real scientists.
We
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LINK to what they already know,
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ACTIVATE curiosity through hands-on discovery
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BUILD understanding that actually sticks.
Inside every bottle of hydrogen peroxide, a gas is slowly escaping. You cannot see it. You cannot hear it. But right now, wherever that bottle is sitting, the liquid is very gradually breaking down into water and oxygen gas.
Normally that process takes days. You are about to make it happen in seconds — using something that is technically alive.
Before you set anything up: what do you think the yeast is actually doing to cause this? Is it adding something? Removing something? Creating a new substance? Write your theory before you touch anything.
You touched the bottle and it felt warm. A reaction that releases heat is called an exothermic reaction. Where did that heat energy come from — and what does that tell you about the hydrogen peroxide before and after the reaction?
The yeast made the reaction happen much faster — but the yeast itself was not destroyed. It is still there in the foam. If the yeast is not used up, what exactly is it doing? Draw a diagram showing your theory of what the yeast did to the hydrogen peroxide.
Pour a small amount of hydrogen peroxide onto a piece of fresh raw potato. What happens? Compare it to what happened with yeast. What does this tell you about what is inside a potato?
You tested yeast and potato. Both made the reaction go. What do yeast and potato have in common — and what does that tell you about where this enzyme is found in nature? Can you think of other living things that might also have it?
A catalyst is something that speeds up a reaction without being used up. Catalysts are used in car exhaust systems to break down harmful gases, and in industrial factories to make chemicals more efficiently.
Based on what you have seen today, explain in your own words why a catalyst is so useful — and why it matters that it is not used up.
"Want the full teacher guide? The Crazy Scientist Lab includes classroom delivery tips, how to manage the WOW moment, differentiation for Stage 2 & 3, — ready to teach tomorrow."
Think Like a Scientist
Scientists don't just do ONE experiment; they change one part of the experiment (independent variable) and then see how it affects another part of the experiment
(dependent variable)
Change ONE variable and test again.
Does the amount of yeast change the reaction — does more yeast produce more foam or a faster eruption, and is there a point where adding more yeast makes no difference?
Does the source of the enzyme change the result — does grated raw potato produce the same reaction as dry yeast, a bigger one, or a smaller one?
🧪 Try it! Change ONE thing and test again. What did you discover?
Want to go deeper? Tap a section below to explore. ▼
The Science Behind It
What's really happening?
Hydrogen peroxide is a liquid that slowly and naturally breaks down into just two things: water and oxygen gas. Normally this happens so gradually you'd never notice — it takes days.
The yeast you added made it happen in seconds. Inside the dry yeast is a special protein called an enzyme — think of it as a tiny key that fits perfectly into the hydrogen peroxide molecule.
The moment that key connects, the molecule breaks apart almost instantly. All that oxygen is released at once, gets trapped by the dish soap, and the foam erupts.
The yeast itself isn't used up — it just keeps working until all the hydrogen peroxide is gone.
Why does the bottle feel warm?
When the hydrogen peroxide breaks down, it doesn't just release oxygen gas — it also releases energy as heat. That's why the bottle feels warm after the reaction.
A reaction that releases heat is called an exothermic reaction. The heat was stored inside the hydrogen peroxide molecules before the reaction and is released when they break apart.
This tells you something important about energy: the reaction moved from a higher-energy state (hydrogen peroxide) to a lower-energy state (water and oxygen).
Almost all reactions naturally move in the direction of lower energy — and release the difference as heat or light.
Why does potato work too?
The same enzyme that's inside yeast is also inside a raw potato. And inside your own cells. In fact, it's found in almost every living thing on Earth.
Your body produces tiny amounts of hydrogen peroxide as a normal by-product of cell activity — and this enzyme (called catalase) breaks it down immediately before it can damage your cells.
Grate a raw potato and pour hydrogen peroxide on it — it fizzes. Same enzyme. Same reaction. Completely different living thing.
The foam you made today is a visible, dramatic version of a process that is happening inside you right now.
Real-world connection
Enzymes like catalase are how living things control their own chemistry. Every chemical reaction in your body — digesting food, building muscle, producing energy from what you eat — is controlled by a specific enzyme that speeds it up to useful rates.
Without enzymes, these reactions would still happen, but billions of times too slowly to keep you alive.
The yeast in this experiment is demonstrating that idea in a way you can actually see — and feel the heat from.
Try next
• Discover another chemical reaction hidden inside a living thing → [The Starch Detective]
• Look at what foam actually is and how its structure forms → [Soap Foam]
Extension: G&T Years 5 & 6
What is an enzyme?
An enzyme is a special type of protein — a large molecule made of folded chains of amino acids — that acts as a biological catalyst. The key feature of an enzyme is its three-dimensional shape.
Each enzyme has a specific region called the active site, which is shaped to fit only one particular type of molecule (called the substrate). When the substrate fits into the active site — like a key fitting a lock — the enzyme triggers a chemical reaction that breaks the molecule apart or joins molecules together.
The enzyme itself is unchanged at the end and can immediately work on the next substrate molecule. One catalase enzyme can process millions of hydrogen peroxide molecules per second.
What makes a catalyst so useful?
A catalyst is anything that speeds up a chemical reaction without being consumed in the process.
Because it's not used up, a very small amount of catalyst can process an enormous quantity of reaction — it just keeps going until the substrate runs out.
In every case, the value of a catalyst is that it dramatically lowers the energy needed to start a reaction, allowing it to happen at room temperature that would otherwise require extreme heat.
You tested both yeast and raw potato — both caused the reaction. Design an experiment to compare the relative amounts of catalase in each. What would you measure, how would you keep the test fair, and what result would tell you which living thing has more active enzyme?
Vocabulary
Enzyme
A special protein inside living things that speeds up a specific chemical reaction. Each enzyme is shaped to work on one particular substance only.
Catalyst
Something that speeds up a chemical reaction without being used up or changed itself. Enzymes are biological catalysts made by living things.
Hydrogen peroxide
A liquid (H₂O₂) that naturally and slowly breaks down into water and oxygen gas. Found in first aid kits. Dark brown bottles block light, which slows the breakdown.
Exothermic reaction
A chemical reaction that releases energy as heat. The warm bottle in this experiment is evidence that the reaction is exothermic.
Substrate
The specific molecule that an enzyme acts on. Hydrogen peroxide is the substrate for catalase — the molecule that fits into the active site and triggers the reaction.
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The Crazy Scientist books
These highly visual books combine storytelling and real science, helping students revisit key concepts and stay engaged long after the session.
Designed by a practising NSW classroom teacher (30+ years experience), these books directly support NSW Science & Technology (2024) outcomes and reinforce “Working Scientifically” skills.
Perfect for classroom libraries or home explorations.
For teachers (YouTube)
— Science Before the Bell
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