Lab Report: What happens if put bones into vinegar.

My son's lab report for studying human bones and learning how a base will dissolve the calcium in bones.   I needed to assist my son in preparing the bones, but otherwise he did the experiment himself.  He asked me to handle the bones after they sat in the vinegar.  He took the pictures.  :)

Hypothesis: Vinegar would weaken the uncooked bone, and it would not weaken the cooked bone in vinegar.   The bones not in vinegar... The uncooked one would not break and the cooked one would break. 

Procedure: We put one cooked bone and one uncooked into vinegar and let them in there for five days.  After five days we took them out too see what would happen.   We put one uncooked and one cooked bone on a plate and left them to sit for five days.

Observation: 
The bones in vinegar were both bendable.  The uncooked bone was more bendable than the cooked bone.  You could bend the ends of the cooked bone but not the middle.   With the uncooked bone you could bend the entire thing.   The ones in vinegar, the cartilage came off, it was gloppy with the uncooked one... spreadout with long strands, the cooked one stayed together but was mushy.  Both bones not put in vinegar were not bendable. 

Uncooked bones in Vinegar

Cooked Bone in Vinegar

Conclusion: Vinegar weakens bones and cartilage.  Letting bones air dry makes them harder.   Vinegar is a base and bases dissolve things.