We had chicken for lunch today and he wanted to try the experiment - so I now have a jar of vinegar with a chicken bone in it on my bench :) He followed it up by creating a poster of foods with calcium in them - I printed out a traceable sheet from http://www.kidzone.ws/tracers/index.htm with the word calcium on so he had some hand-writing practice, and then he went to town with the scissors, glue & a bunch of grocery catalogues!
After he'd finished, I got out the 'Disney' kid's encyclopedias and we read what calcium was, and looked at pictures of skeletons.
So there's science for the day!
The chicken bone in vinegar :)
Making the chart
The finished product