Disappearing Minerals

This is a classic science investigation because it is easy and it is fun.
First take an uncooked egg and plop it in a glass or jar of water. Watch it for a bit and see it form bubbles as the calcium in the eggshell is starting to dissolve. Now, pour that out and add vinegar instead. Set aside for several days.

After about a week the egg will look like this.
The shell disappears entirely and all you have left is a little membrane.




You can do a similar demonstration with a chicken bone. Test a clean and dry chicken bone to see how difficult it is to bend. Be careful, though, you don't want to break it! Now put the bone in vinegar, covering it fully. Keep the bone in the vinegar for about a week. You can test it's flexibility each day but if you do, put it back into the vinegar when you are finished testing it. Is it getting more flexible?

The vinegar dissolves the minerals in the bone, leaving primarily just the collagen, which is what makes bones flexible.

Popular Posts