In this activity, students see that without calcium, bones become floppy.
Although bones in museums are dry, hard, brittle or crumbly, the bones in your body are very different. They are alive, growing and changing all the time like other parts of your body.
Bones have 2 main components:
- Inorganic compounds ~70%. Primarily Apatite : a hard mineral that contains calcium and makes them stiff.
- Organic compounds. ~ 30%. Primarily Collogen: a rubbery protein component that makes them strong.
Stiffness is an indicator of the ability of a bone to remain in/return to an original form after being subjected to a force.
Strength measures how much stress can be applied before a bone deforms permanently or fractures.
If you leave bones in a warm place for a long time, they get brittle because the collagen decomposes or dries out, losing it's "rubbery" flexibility (that's why you have to let a wishbone dry before trying to snap it).
Leaving bones in an acid like vinegar will dissolve the apatite out of the bone, making them floppy.
Use this demonstration to show what would happen if your bones didn't contain calcium.
FunFact: The furcula ("little fork" in Latin) or wishbone is a forked bone found in birds and some other species of dinosaurs, and is formed by the fusion of the two clavicles (collar bones).