Saturday, March 9, 2013

Water density and floating egg experiment

This experiment was suggested by a fan of Nerdy Science, Stephanie, as a fun experiment to do with eggs.

Experimental Questions:
Are eggs denser than plain water? Are eggs denser than salt water?

When things are more dense than water, they sink when placed in water. If they are less dense than water, they float.

Test your knowledge to form your hypothesis (educated "guess"):
Gather a few items from around the house and see if they sink or if they float. Which items are more dense than water? Which items are less dense than water? Can you guess what will happen to the egg when placed in water? Do you think anything different will happen to the egg when placed in salt water?

-1 glass of plain tap water
-1 glass of plain tap water + salt (amount varies)
-1 or 2 raw eggs, non-cracked

-Gently drop an egg into the tap water. What happened?
-Gently drop an egg into the salt water. What happened?
-Add more salt to the salt water. Did that change any of your results?

Our Results:
Our egg in plain water sank to the bottom of the cup.

Our first attempt at the salt water resulted in our egg being neutrally buoyant and hovering above the bottom of the cup:

So, we took a guess about what would happen if we added more salt. Based on the semi-floating egg above result, J guessed that the egg will "really float" when we added more salt.

He was right!

Conclusions (via J's own words):
-"Water can't hold up the egg."
-"Water with salt CAN hold up the egg. Science is amazing!"

The egg is more dense than plain water, but with enough salt, the egg is less dense than salt water.

Thanks, Stephanie, for this fun addition to our egg experiments!