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!
- One egg
- Clear container: I used a wide jar, but a tall glass would work and you won’t need as much salt
- A few cups of salt
- Spoon to mix the solution
Place the egg in plain water and talk about whether or not it floats. Pretty simple — it most definitely sinks!
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?!