It's a great visual and tactile experiment to do at home and there are quite a few things that you can talk about with the kids.
You want at least two clear glasses. One to add vinegar to (white is better visually but you can use dark vinegar) and one to add water to. The water is the control substance that will do nothing to the egg and keep it exactly the same. If you have enough glasses and the ingredients you can also use a glass of fizzy drink (we used coke) and a glass of fresh fruit juice (we used orange juice).
Place the same sized egg in each glass and cover with each of the liquids you're using.
We left the eggs for 24 hrs and when we looked found ...
- The water hadn't done anything
- The coke had surprisingly dissolved very little.
- The orange juice had dissolved quite a bit
- The vinegar had dissolved loads
We put the eggs back in their liquids and left for a further 12 hour and found ...
- The water still hadn't done anything
- The coke had dissolved a little but more.
- The orange juice had dissolved quite a bit more
- The vinegar had dissolved all of the shell
Now what you may have noticed is that the egg with no shell is also a LOT bigger than the control shell. This is because the membrane around the egg is semi permeable.
Whilst it was in the vinegar the liquid moved through the membrane into the egg resulting in the membrane swelling and increasing in size.
When you hold the egg with no shell it will feel damp to the touch and that's because the liquid is starting to seep back out through the membrane. You can see this really well if you put the shell-less egg on some kitchen roll. The liquid in the shell will soak into the kitchen towel through the membrane.
And there's more!
The egg without it's shell and now full of extra liquid, will bounce!
But how high will it bounce?
We cut lengths of wool approximately 10cm in length to hold up as a guide to height. How high do you think we got?
Please have a look at all the other blogs that have had fun dissolving eggs in vinegar and please add yours to the list if you have one.