The Bone Bender
Inside every bone in your body there are two completely different materials working together. One makes bone hard. One keeps it from snapping. Take one away — and what is left behind will change the way you think about your own skeleton.
7-12 yrs
Easy
15
min
Stage 2, Stage 3
Mission Briefing.
Designed by Darin Carr (BSc, DipEd)
NESA Accredited Teacher Chemistry & Physics Specialist
Creator of the LAB™ Learning System
Professor Picklebottom
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The Bone Bender
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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.
Mission Equipment
Clean chicken bones — drumstick
White vinegar
A glass jar or tall cup large enough to fully submerge the bone
Optional: lemon juice and cola — for acid comparison
Optional: a ruler or protractor — for measuring bend angle
Let’s Investigate
1
Prepare your bones
Start with clean chicken bones — a drumstick bone works well, as does a wishbone or a wing bone.
Remove all meat from the bone and rinse it thoroughly. Pat it dry.
3
Make your predictions
Write down your predictions before placing the bone in vinegar.
Will the bone change?
How long do you think it will take?
5
Observe
Check the bone once a day without removing it from the vinegar.
Look for: the bubbles on the bone's surface, any visible changes to the bone's colour or texture, and any cloudiness in the vinegar.
7
Comparing cartilage
Hold the bent bone and squeeze the tip of your nose again with your other hand.
Compare the two feelings — the soaked bone and your nose cartilage.
Now think: your nose and ears are made of cartilage, not bone. Cartilage is collagen without the calcium mineral.
2
Before you start
Before you place the bone in vinegar — squeeze the tip of your nose gently between two fingers.
Bend it. Let it go.
Do the same with the top of your ear. Notice how those structures are flexible and springy, not rigid like a bone.
4
Submerge the bones
Place the bone in a glass jar and cover it completely with white vinegar.
Make sure the entire bone is submerged.
Put a lid or cling wrap loosely over the top to contain the vinegar smell. Leave it at room temperature and do not disturb it.
6
Testing the bone
After three to five days, carefully remove the bone from the vinegar and rinse it gently with water.
Now try to bend it.
Compare it to the fresh bone you tested in Step 1.
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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.
You already know that bones are hard. But have you ever thought about WHY they are hard — what is actually inside the bone that makes it rigid?
Squeeze the tip of your nose. Bend it gently. Does it feel like the rest of your skeleton — your arm, your shin, your knuckles? What is different about your nose compared to your arm?
Your nose is made of cartilage, not bone. Cartilage is flexible. Bone is rigid. But they are actually made of some of the same ingredients — just in different amounts.
Predict: if bone and cartilage share some ingredients, could you ever turn a bone into something that behaves like cartilage? What would you need to remove — or add — to make that happen?
Think back to the bubbles you saw forming on the bone from day one. What were those bubbles — and what does the fact that they appeared immediately tell you about what was happening inside the bone from the very first moment it touched the vinegar?
Recall the daily changes you recorded. Did the reaction speed stay the same throughout — or did the bubbles slow down over time? What does that suggest about where the calcium was sitting inside the bone and how the acid had to work its way in?
When you squeezed the soaked bone and then your nose, what did they have in common? What has vinegar effectively turned the bone into — and what ingredient was removed to make that happen?
The bone kept its shape even after going rubbery. What does that tell you about the collagen framework — is it just filler, or is it actually doing structural work inside the bone?
Bone is a composite material — two ingredients working together. Engineers use the same principle in almost every strong structure on the planet.
Reinforced concrete combines concrete (strong under compression, brittle under tension) with steel rebar (flexible under tension).
How is that the same partnership as calcium and collagen in your bones?
What does each ingredient contribute — and what would happen to a building made of concrete alone?
"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 type of acid change how quickly the bone softens? Compare white vinegar, lemon juice, and cola — all three are acidic but at different concentrations.
Does the type or size of bone make a difference?
🧪 Try it! Change ONE thing and test again. What did you discover?
Dr Puddledrip’s Science Tip
Want to go deeper? Tap a section below to explore. ▼
The Science Behind It
Bone is not a single material — it is a biological composite, meaning it is built from two fundamentally different substances working together.
The first is collagen, a protein that forms long, interwoven fibres throughout the bone's structure. Collagen is tough, flexible, and resistant to being pulled apart — it gives bone tensile strength, the ability to resist snapping under a bending force. On its own, collagen is rubbery and bendy, like the cartilage in your nose and ears.
The second is calcium mineral — primarily calcium phosphate in a crystalline form called hydroxyapatite, with some calcium carbonate. This mineral is deposited throughout the collagen framework during bone development, hardening it into a rigid structure that resists compression and supports the body's weight.
Together, these two materials give bone a remarkable combination of properties: hard enough to support the body and protect organs, yet flexible enough to absorb shock without shattering. Engineers recreate this same principle in composite materials: reinforced concrete (concrete plus steel), fiberglass (glass fibres plus resin), and carbon fibre all use two materials — one rigid, one flexible — to produce something stronger than either alone.
Extension: G&T Years 5 & 6
Vocabulary
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READY TO TEACH THIS
TOMORROW?
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