A couple of weeks ago, we went to Summer Reading at the library, and learned all about viscosity, and the dead sea. The dead sea is such an interesting place, and this little experiment helped to solidify some of those neat facts for my boys. They were excitedly telling their daddy all about the dead sea, days later.
So, I decided to recreate the experiment and share with you all. The best thing is that this experiment uses basic household supplies that you most likely have in your pantry right now.
- A clear glass–deep enough for the egg to sink or float. I used a pyrex measuring cup because I wasn’t sure how much salt I would need for greater amounts of water. I used about a cup of water.
- Water–deep enough to clearly tell if the egg is sinking or floating
- 1 egg
- Salt–we used, maybe, a few tablespoons
- Measuring spoon
- Stirring spoon
(The lego guy is totally optional ;) My 4-year old snuck him in there right as I was getting ready to take this picture.)
Will the Egg Float?
Ask your children if they think the egg will float. Demonstrate that it sinks (make sure the egg isn’t bad! lol…apparently bad eggs can float, but that’s not really what we’re going for here).
No bad eggs here, ours sank right to the bottom.
At this point, we talked a bit about the dead sea and it’s salt content, and how people can easily float on the dead sea because of this. Then I asked them if there is anything we might be able to do to our water to get the egg to float.
We added a scoop of salt
And stirred it in
At this point, the egg still sank. So, we added more salt, one scoop at a time. And eventually…
It’s kind of hard to tell from this picture, but my 4-year-old’s excited face gives it away…yes, the egg is floating at this point. Now, they got to have some fun with it.
Push the egg down to the bottom, and what happens?
It bobs right back up. Both boys loved that.
I had intended for this to be a more “scientific” experiment (i.e. how much salt must we add to 1 cup of water to make it dense enough for the egg to float.). However, this didn’t exactly work out for us because (a) I was holding the camera and they were too excited to keep track of the scoops added in, so we didn’t count very well, and (b) they didn’t stir very well either, so there was a lot of loose salt at the bottom not mixed in.
However, this could be a fun little experiment to allow your children to make some educated guesses, or hypotheses, about whether or not the egg will float and/or how many teaspoons of salt it might take before that happens.
Have you tried this experiment? Did your kiddos enjoy it?