Density is not magic!

Hi! I’m back! So, I was thinking about eggs the other day. Specially, floating eggs. Yes, I am very much aware that normal human beings don’t usually think randomly about eggs. Well, of course, unless you raise chickens. Or you work in an egg distribution center. Or you work in a grocery store and you stock the eggs. Or you are a baker who ran out of eggs. Whatever, generally speaking, random thoughts about eggs, well, are random. It is the floating part that is the key here, right now!

Eggs have mass. Why? Just because they do. They are made of solid substances and they have a liquid inside of them—provided they are not hard boiled—and therefore, they have mass and, ergo, sink. But what if it didn’t. Well, it is possible that you have an egg floating in salt water. Of course, it is also possible that your egg is bad, in which case, you might want to get rid of that egg. Just saying. Anyway, I digress. Using an egg is a great way to check the density of salt water. Huh? Actually, it is a great way to see how a solution of salt (Soduim Chloride) and water (H20) becomes denser then an egg (yes, I looked it up. I wanted to say “more dense” but denser is a word when comparing densities or two or more substances). Here, let me show you.

Oh, first, let me introduce you to my helpers today: Dawson, Boomer and Colt. I am not sure how much help they will be, but they listen to me when I talk!! That’s all that counts!


Anyway, let us be back to our task. First, you need your equipment.

I used a candle holder for my glass, but a plain glass would work to. I used a teaspoon (I forgot it in the first picture!),

a bowl of salt (I didn’t measure it),

water (warm tap water works—remember, salt dissolves in warm water faster than cold. My water came in at 88.7 degrees Fahrenheit, or 31.5 degrees Celsius)…(oh, and it was 2 cups).

So, I poured the water into the glass and then added the egg.

Note the egg is not white—it’s green! No, no green eggs and ham here, Sam I am! No, these eggs are fresh off the farm. I don’t know what the name of the chicken is that lays green eggs, but they all taste pretty much the same. Sorry—I digress—again!

Then, I put in one teaspoon of salt.

I did use the measuring device to swish (yes, that is the technical term!) the water about to help a solution form. I stopped and waited to see what would happen…which was nothing!

I added a second teaspoon. Did the same thing…nothing…

I added a third teaspoon. Did the same thing…nothing…

I added a forth teaspoon. Did the same thing…nothing…

Seeing the repetition here, by any chance?
I added a fifth and a sixth teaspoon. Did the same thing…nothing…
At this point, I am wondering if my experiment is going to be a bust!

I added a seventh teaspoon. Did the same thing…nothing…
I added an eighth teaspoon. Did the same thing…nothing…

Note how cloudy the solution is getting. And while there is quite a bit of salt on the bottom of the glass, a large majority has been incorporated into the water…

Actually, now that I mention it, I guess I never explained what is happening here. You see, the egg is denser then water, and the salt is denser than water. When you add salt (NaCl) to water (H20), the salt molecules take in the water molecules. This makes the salt heavier than the egg, making it denser. What happens when you have a more dense substance and a less dense substance together?

Yep, that’s right-- I added a ninth teaspoon. And the egg floated! 

So there you have it. Very cool, no magic involved! Just science! 

Now, there are several ways you can change the variables in this experiment. You could, say, change the temp of the water—see how many teaspoons of salt to get the egg to float in cold water. Or, you could change the type of salt. I used regular, old fashioned, non-iodized salt. 

By the way, iodized salt is salt that has small amount of iodine incorporated with it. They did this to help prevent iodine deficiency which causes developmental and intellectual issues in humans. Sorry! I digress again! 

Anyway, I have to say this was a fun experiment to show you. I hope you all enjoyed learning along with me and I hope you go and play with it yourself! Let me know what you did different and what your results were!



Educational Blogger

About the Educational Blogger

Emma Merlo studied theater and music at Austin College for four years, and toured nationally with the Missoula Children’s Theater for two years.  She has taught kids all over the US from age 2 to age 18. She loves science education and especially space!