Ok, so maybe it didn't work quite like we expected. Leighton suggested using warm water so the salt dissolved faster or stirring after each additional teaspoon. Regardless, our salt water was definitely dense enough to hold up the egg. And the kids had fun. (You should see all the video footage that was cut-out. Zac especially had fun boinging the egg into the water and watching it bounce back up again!)
We learned something and had fun at the same time. That's what homeschooling is all about!
Here is what you need if you would like to try this at home:
1. Start by placing the egg in the drinking glass. Fill the glass 3/4 with water.
2. One at a time, pour a teaspoon of table salt into the water, until the egg floats.