Eggs aren’t just for breakfast…they can be fun and fascinating too! Try your hand at a few “eggs-periments” that highlight the unique properties of the amazing egg.
The Spin Test
Materials
A raw egg. A hard-boiled or hard-cooked egg. A flat surface on which to spin.
Method. Spin the raw egg and the hard-boiled egg at the same time on a large flat surface.
Whichever egg spins better (smoothly without wobbling) is the hard-boiled egg.
For a neat variation, spin them both again then stop them. Quickly release them and watch the raw egg. It should continue moving even though the hard-boiled egg has completely stopped.
Explanation. The yolk and white in a raw egg slosh around unevenly as it spins, making it impossible to spin it smoothly while the solid yolk and white in the hard-boiled egg enable the egg to spin smoothly.
The raw egg will continue to move even after you have stopped it and then let go of it because the liquid inside is still moving around.
Fun with Naked Eggs
Materials
At least 2 naked eggs. 2 clear cups large enough to hold an egg plus some liquid. Corn syrup. Water. Food colouring. A spoon or ladle.
Method. Put a naked egg into one of the cups and add enough corn syrup to cover the egg.
Put another naked egg into another cup and add enough water to cover it and a few drops of food colouring.
Put both cups into the refrigerator for 24 hours.
After the 24 hours you should have one nice and plump egg in the water and one shriveled and flabby egg in the corn syrup.
Explanation. The membrane of the naked egg is selectively permeable–it lets some molecules through and blocks others. Water (mixed with food colouring) moves through the membrane easily but bigger molecules (like sugar molecules in the corn syrup) don’t.
In the corn syrup cup, the water molecules from the egg white (which is 90 per cent water) have moved through the membrane to the corn syrup (25 per cent water) causing the naked egg to shrivel and go limp.
Naked Eggs
Materials
A raw egg. White vinegar. A container big enough to submerge the egg. A spoon or ladle.
Method. Place the egg in the container so that it does not touch the sides and add enough vinegar to cover the egg. You will already see bubbles forming on the egg.
Cover the container and put it in the fridge for 24 hours.
After the 24 hours have elapsed, scoop the egg out of the vinegar being careful not to break it. Dump out the vinegar and cover the egg with fresh vinegar. Leave the egg in the fridge for another 24 hours.
Scoop out the egg and rinse carefully. Throw away any broken eggs.
You should now have a translucent egg without a shell. It is being held together by its membrane which while flex if you squeeze it.
Explanation. The acetic acid in the vinegar breaks apart the calcium carbonate crystals that make up the egg shell into separate calcium and carbonate parts. The calcium parts float while the carbonate makes the bubbles that you see.
