The Bouncy Egg Finale

Three days ago my daughter and I put an egg (regular, not hard-boiled) into a jar of vinegar.  To be honest it was apple cider vinegar since we ran out of regular vinegar.  Two days ago we replaced the old vinegar with new.  Today it was time to take the egg out of the vinegar and observe the effects.  Below is a picture of our vinegar soaked egg on the left and another egg from the same carton.

Left - Vinegar soaked egg.  Right - egg from same carton

There are a couple of clear differences which my daughter and I discussed.  She immediately picked out the color difference.  The vinegar ate away the outer shell.  The other difference is size.  The vinegar soaked egg is larger!  We both thought this was very cool.  The vinegar soaked egg felt rubbery and did indeed bounce when dropped from a few inches above the counter top.  I planned on showing a video, but my daughter got a bit ambitious and squeezed too hard when picking it up.  No harm though.  We saw it bounce and my daughter proved to everyone reading this that the yolk of the egg is not hardened or thickened in this process.  Below is the leftover mess when the egg broke.

Broken vinegar soaked egg.  Messy!

"Shell" created by vinegar.

The brownish thing in the second picture is not the original egg shell.  It's a second "shell" created by the vinegar soaking process.  It's very fragile as we quickly found out.  

To conclude, this was a very cool science project for my 5 year old daughter.  All that was required was an egg, vinegar, a jar, and 3 days worth of patience.  It's a fun activity that I would definitely recommend to you and your kids.