Science is my kid’s favorite subject. He’s been fascinated by cooking from an early age, and we thought, hey, this kid likes food! But no, he does not like food (unless it’s yogurt, candy, or macaroni and cheese, and absolutely nothing else). What he really likes is experimenting – pouring and mixing and hoping something will explode (he is a boy, after all)!
So, I’m always looking for easy experiments we can do together, and when I saw this density experiment with eggs and saltwater over at The Stay at Homer, I knew we would try it. So easy! Then I saw this on Pinterest:
It’s a naked egg! You can find out more about the science behind this phenomenon from the original source of the photo, Imagination Station Toledo. Basically you just soak the egg in vinegar and the shell disolves, see below.
Making a Naked Egg
We soaked three eggs because we needed two. This makes perfect sense to anyone with kids.
It takes about two days of soaking to dissolve the shell. You will need to rub it gently with a paper towel to get it all off. And voila! A naked egg.
If you hold it up to the light you can see the yolk. If you drop it 1 inch it bounces, if you made extra eggs go ahead and see what happens when you drop it further than that.
What’s This About Osmosis?
I learned that eggs are about 90% water, so if you put the egg in water, the egg will absorb water through it’s membrane until the water content is equalized. This is known as osmosis. We used colored water so we could clearly see the water was absorbed.
If you put the egg in a substance with low water content (e.g. corn syrup), the egg’s water content will decrease, resulting in a shriveled naked egg. Yes, it looks and feels gross!
Saltwater and Density
Next, putting aside the naked eggs for a moment, we got out a raw egg, shell on and put it in a glass of water. It sunk.
T added plenty of salt to the glass, gave it a stir, and….it floats. This is of course because the density of the egg is now less than the density of the saltwater.
Next we tried the naked eggs (one shriveled, one red) in the saltwater. I won’t tell you what happened, because you like some surprises, right? But I will say they don’t all float.