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Why are our bones so strong?

This week I’ll show you how to make a bendy bone, it’s one of my favourite science activities because it creates a real sense of awe…we can turn something that seems so strong and rigid into something flexible! It defies our expectations and it’s a really simple way of exploring what’s inside our bodies. Let’s discover the answer to “Why are our bones so strong?”

Why are our bones so strong?

Underneath our skin is the skeletal system, formed of 206 bones our skeleton is responsible for protecting us e.g. skull protects our brain and ribs protect our lungs and heart.

It also helps to support our bodies, giving us strength and rigidity- imagine having no bones, what might you look like?!

Our bones are also responsible for helping us to move with some help from our muscles, ligaments, tendons and cartilage.

Why are our bones so strong?

You will need:

  • Clean, dry chicken leg bone (boiled for 30 mins)
  • Lidded container
  • White vinegar


  1. Hold the bone in your hands and try to bend it (don’t force it so much it snaps!)- does the bone bend?
  2. Now pop the bone in your box and cover it with vinegar. Leave it for 3 days.
  3. After 3 days take a look at the bone, pour away the vinegar and replace it with fresh vinegar,
  4. Leave the bone in the vinegar for another 3 days, then remove it and try it off. How try bending the bone- what happened?

Bones are made of calcium carbonate and a soft material called collagen, by submerging the bone in vinegar, an acid, we dissolved the calcium carbonate away leaving only the collagen behind. We need calcium to make our bones strong, without it our bones become soft and more likely to break. The collagen alone isn’t strong enough to support our bodies, which is why it’s important to eat foods with calcium in like milk, cheese and yoghurt.

This activity is one from “X-Ray- What’s inside?”, an exploration of our muscular and skeletal systems.

The Virtual Explorers Club is a monthly e-magazine and online STEM activities library, created by Ruth Tsui, an experienced primary school teacher and STEM educator. Designed to engage and excite primary school children in hands on STEM learning, supporting you to develop key life and learning skills e.g., resilience, collaboration, critical thinking and many more. The library itself is full of hands-on activity ideas, linked in themes to support you as you explore- all the background information, written guides and supporting videos using household supplies or items available in the supermarket.

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