100 Days of Science #18-- Floating Eggs

We watched a super fun marine biology class on the computer a couple of weeks ago and at the end of the video we were given a list of fun experiments to try at home.  We could not wait to dive in!

I already had all the ingredients needed to try floating a hard boiled egg in salt water so that's what we started with. It was a lot of fun and I actually encouraged each boy to try this one on their own.

For this experiment you will need:

A hard boiled egg (we used one each)
A clear jar big enough for the egg to move up and down freely
a spoon or stick for stirring

We began by filling each glass about half way with water.  You want to make sure the water completely covers the egg.  At this point the egg will be lying nicely along the bottom of the glass.

My kids began slowly adding salt to their glass.  They had some debate about whether sea salt or regular table salt would work better so they experimented with different kinds.

As they poured the salt in they periodically stopped to stir up the salt.  Sometime they stirred around the egg, other times they tried removing the egg/ stirring/ and then putting it back in.

It took a LOT of salt before we began seeing the egg move away from the bottom of the glass.

Evan, who used only table salt, was the first one to get his egg to float all the way to the top of the glass.

I then asked him if he could get his egg to float or suspend between the top of the glass and the bottom so he added just a little bit of water.

As the salt settled to the bottom we could more clearly see his egg "floating" in the middle of the glass
 Alec was next to get his egg to float! He quickly added a bit of water and managed to get his egg to float too.

Ian used the most salt (can you see it all in the bottom of his glass?)  His egg floated right to the top and he really didn't have room to add any more water.

He found just a tiny bit of water made the egg sink a bit and it looked so neat when some of the salt settled back down and the water cleared up just a bit.

This was such a fun experiment learning about density and buoyancy. 

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  1. Love this one..quite "Egg"cellent!!

  2. You could talk to the boys about what happens to the when swimming in a lake vs a ocean. Then bring up is there any places to swim that are super salty in the world? And what would that be like. Great project.

    1. Living on the lake and so near to the ocean we did talk a bit about that; of course they realize that the ocean near us is not salty enough to make much difference but we did once watch a video of a family that went "swimming" in the dead sea.

  3. What a cool experiment! I love the looks of curiosity and focus on the boys' faces. Clearly they love learning!

  4. My son will love this floating egg. He loves doing science experiments. Thanks for sharing at #HomeMattersParty


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