As I hovered the egg over a jar of water, I asked my 3.5 year old, “Will it sink or float?”and it reminded me of Dave Letterman’s funny sketch, “Will it Float?” Have you seen it? This science experiment is really easy to set up + clean up, and the lesson learned on the density of water actually stuck with my 3-year old daughter long after the experiment was over. Fun and success!
Supplies
- One egg
- Clear container: I used a wide jar, but a tall glass would work and you won’t need as much salt
- Water
- A few cups of salt
- Spoon to mix the solution
Step #1:
Place the egg in plain water and talk about whether or not it floats. Pretty simple — it most definitely sinks!
Step #2:
Start adding salt to the water. We added ours little by little, and tested the solution by adding the egg back into the water. My 3 year old poured while my 1-year old mixed. I love these moments when they work and play side-by-side.
Finally, it floats!
My little one loved this step, as she could finally reach the egg, and had some fun picking it up and dropping it back into the water where it “bounced.”
The Science behind the Experiment
The egg won’t float in regular water because it’s heavier than the water. But adding salt to the water makes the water more dense than the egg, and it floats! We have a book called “Let’s Visit Israel,” and my 3-year old will talk about this phenomena when we reach the page about floating in the Dead Sea.
Taking it one step further
Steve Spangler Science has a great idea for dragging this out into one more step. Fill half of a tall glass (that an egg will fit in) with this salty solution and then slowly pour plain tap water down the sides of the glass, being careful not to mix the two solutions. Gently drop the egg in the solution and watch it sink past the plain water, only to stop on top of the salty water! How cool is that?!
What a fun experiment! One of my (undeclared) goals this year is to do more science experiments with my daughters. We just did the naked egg experiment and that was fun, we’ll really have to give this a go. I LOVE Steve Spangler!
Steve Spangler is a favorite! We love to do the naked egg experiment as well!
Could also be used to find out if an egg is old – stale eggs will float!
We did this experiment when we learned a bit about Israel (I go there quite often on business trips). I called it “The Dead Sea” experiment. Our personal favorite is penny cleaning.
Very cool! Can’t wait to try this with my kids.
Have you left an egg soaking in white vinegar to see what happens? It’s an easy, interesting experiment (and I won’t give the final result away for anyone curious to give it a try). 🙂
Whoops, just read the other comments and it sounds like everyone knows about the naked egg trick already! Oh well, it’s a good one.
Great experiment! Be careful to use fresh eggs however, because the older an egg gets the more air is contained inside the shell, which will make it float. The “sink or float” experiment is actually how we test to see that our eggs are still fresh!
one of our facebook fans said you can do the same thing with a CARROT!!! Â give it a go! Â who knew??!?!
i love this experiment
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thanks i learned in this experiment