(
If you've scoped out the American POP exhibit you might've found Harry Potter's invisibility cloak and wondered... can I make something invisible? In this activity from the Exploratorium, the average egg from your kitchen can disappear! Watch an eggshell become invisible using just a few materials from around your house.
Materials
- A few eggs
- White vinegar
- A container big enough to hold all your eggs and a cover for the container
- A big spoon
Process
- Place your eggs in the container so that they are not touching.
- Add enough vinegar to cover the eggs. Notice that bubbles form on the eggs. Cover the container, put it in the refrigerator, and let the eggs sit in the vinegar for 24 hours.
- Use your big spoon to scoop the eggs out of the vinegar. Be careful—since the eggshell has been dissolving, the egg membrane may be the only thing holding the egg together. The membrane is not as durable as the shell.
- Carefully dump out the vinegar. Put the eggs back in the container and cover them with fresh vinegar. Leave the eggs in the refrigerator for another 24 hours.
- Scoop the eggs out again and rinse them carefully. If any of the membranes have broken, letting the egg ooze out, throw those eggs away.
- When you’re done, you’ll have an egg without a shell. It looks like an egg, but it’s translucent—and the membrane flexes when you squeeze it. Very cool!
Results
When you submerge an egg in vinegar, the shell dissolves. Vinegar contains acetic acid, which breaks apart the solid calcium carbonate crystals that make up the eggshell into their calcium and carbonate parts. The calcium ions float free (calcium ions are atoms that are missing electrons), while the carbonate goes to make carbon dioxide—the bubbles that you see.
Want more Saturday Science? See all of our at-home activities on the blog or Pinterest.
