Bendy Eggs & Chicken Bones
What you need:
- 1 egg (hard boiled)
- 1 cup vinegar
- Jam jar or clear drinking glass
Directions:
- Pour 1 cup of vinegar into jar
- Add the egg
- What do you see (bubbles rising from the egg)
- Leave the egg in the vinegar for one day.
- Remove the egg and feel it.
- Record your observations (the egg shell will be soft)
What happened:
Eggs contain "calcium carbonate". This is what makes them hard.
Vinegar is an acid known as acetic acid.
When calcium carbonate (the egg) and acetic acid (the vinegar) combine, a
chemical reaction takes place and carbon dioxide (a gas) is released. This is
what the bubbles are made of.
The chemical reaction keeps happening until all of the carbon in the egg is
used up -- it takes about a day.
When you take the egg out of the vinegar it's soft because all of the carbon
floated out of the egg in those little bubbles.
Follow on exercise
Leave the same egg sitting out on the table for another day.
Now feel it again.
It's hard!
The calcium left in the egg shell stole the carbon back from the carbon
dioxide that's in the air we breath.
Bendy Chicken bones!
What makes our bones hard? That's right! Calcium carbonate -- the same thing
that made the egg shells hard.
Take some thin chicken bones (the wing or wish bones are good) and drop them
in vinegar for a day. Take them out and they'll be soft just like the egg shells
were.
Now you can tie them in a knot, just like a piece of string.
Leave them sitting out on the table and they'll get hard again!
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