This is THE coolest science experiment in the world.
It's cheap and simple and has amazing results. 
That means it's my kind of science!

First, you put some cleaned up chicken bones in a container:

With me so far?

Then you pour vinegar over the bones:

We still good?

Then you put the lid on the jar:

See? Even I can do that!

Now you just put it aside for two weeks.

Ok, we had unexpected company so ours sat for two weeks and two days.
No problem! Just make sure it's at least two weeks...

I won't show you the results since it would ruin all the fun.
But it is amazing!

Knowing that the acid in vinegar dissolves calcium-
Ask the questions:
1. How have the chicken bones changed?
2. What would happen to our bodies without calcium?

And if you want to go further with it:
Bones and Calcium