Materials
Materials:
1 Hardboiled Egg
Vinegar
Clear, Wide-Mouth Glass or Jar
Process:
1. Place your egg gently in your glass or jar.
2. Cover with vinegar. At this point, you will see bubbles begin to form on the outside of the egg as air escapes through the eggshell’s pores.
Bubbles Forming as Air Escapes
3. Let your egg sit for about 24 hours.
4. Remove the egg from the jar and hold it under slow running water as you gently run your finger over the surface of the egg.
Gently Rub Off Shell
5. Continue rubbing your fingers over the egg to gently remove as much of the shell as you can. It will appear as a white, chalky residue on your fingers.
Shell Residue
6. Dump out the old vinegar and replace it with new vinegar. Let the egg sit for another 24 hours and try to gently wipe off the shell under water again.
7. Repeat step 6 as needed until you remove the entire eggshell.
What happened?
Air Pocket
An eggshell contains calcium carbonate. As an acid, vinegar dissolves the shell, forming carbon dioxide, which can be observed by the “foam” you may have seen after the first 24 hours. You’ll notice that after gently removing the shell, the egg membrane is still intact. You can see it best by finding the little pocket of air created at the tip of your hardboiled egg.
Variation:
This experiment will also work with a raw egg, so give it a try if you’re brave! Just make sure you don’t put too much pressure on the egg. Be sure to hold it over the sink as you remove the shell… just in case!
Greensboro Science Center 