A few months ago, I purchased a book titled Tinkerlab: A Hands-On Guide for Little Inventors by Rachelle Doorley.
I like to have a few of these type of books around for the days when we need something to do and I’m out of ideas. Last week, Kellen and I were having such an afternoon. Kellen is a big fan of experiments, so I quickly located an easy experiment for us to complete from the Tinkerlab book called the “Naked Egg” experiment.
The photos and description in the book did not do the experiment justice. Perhaps because they used yellow food coloring, the egg, to me, simply looked like a hardboiled egg. The text described playing with a slippery egg, and I again thought “how much fun is playing with a hardboiled egg?” But we had all the ingredients, so I thought we’d give it a try.
The first step was to gently place an egg into a jar or container.
Step two was to pour enough vinegar to completely cover the egg. I didn’t tell Kellen it was vinegar. Before pouring, I asked Kellen what he thought we were going to pour on the egg, and he said water. I replied that it looked like water, but it wasn’t, and asked him how he might determine it was something else. He smelled it and replied “it’s vinegar!” This is a simple experiment, but can become more complex by asking questions that get your little one thinking.
We added some liquid watercolor to the vinegar. You can also use food coloring. At this point, I asked Kellen what he thought was going to happen as we let the egg soak over night. He replied “it’s going to turn red.”
Kellen observed that the egg was covered with bubbles.
After a few minutes, a ring of foam started to appear on the surface of the vinegar.
We left the egg over night, swishing it around every few hours to ensure the entire egg spent some time in the vinegar.
The next day, we took the egg out of the jar, and placed it in a glass dish to play with. We were surprised to learn the shell had completely disappeared- a naked egg! The shell is calcium carbonate and dissolves as a base when mixed with an acid, vinegar. That’s where all the bubbles came from! Kellen loved the color and texture, and was thrilled to learn the egg could be GENTLY bounced.
The egg felt VERY rubbery. We couldn’t figure out if it was solidified only on the outside, or all the way through the egg. We took the egg outside and held it up to the sun. We also shined a flashlight underneath it.
We soon learned the egg was NOT solid all the way through. Liam dropped the egg a little less gently, and the egg burst. Good thing we had that dish underneath it.
The outside of the egg solidified into a membrane similar to the texture of a deflated balloon. Inside the egg was just the same as if you cracked a raw egg.
The book advised to try the experiment again with different solutions- corn syrup, salt water, etc. We can’t wait to give it another go!