With Easter right around the corner, you may be boiling and dying eggs.
Have you ever eaten a hard-boiled egg? They're pretty delicious, and making a boiled egg is kind of a neat experiment in itself. When it's boiled, you can peel off the shell and the egg inside keeps its shape!
But did you know that you can make an egg shell disappear - while the egg inside keeps its shape - with no cooking involved?
In this week's 20 Minute Lab, we'll make a naked egg using a few things from around the house.
Bonus Experiment! We'll also go a bit further and change our naked egg's shape! We'll make it bigger and smaller by changing the solutions the eggs are soaked in. Remember though, these eggs aren't for eating - they would taste disgusting! Remember, we never eat our science experiments! ;)
Just an FYI: The hands-on time involved in these experiments is very short, but there's a lot of waiting time. Be prepared for the science to work its magic overnight while you sleep!
If your egg's shell is still hard after 24 hours, you may need to leave it for another day...
WHAT'S GOING ON?
What do you see? Where did the shell go? Does your egg feel rubbery and bouncy? How did that happen?
The shell of an egg is made of calcium carbonate. Vinegar contains acetic acid.
When the acetic acid in the vinegar comes in contact with the calcium carbonate in the egg shell, a chemical reaction happens, which dissolves the egg shell!You might have noticed that bubbles formed around your egg after you poured in the vinegar. The chemical reaction produces carbon dioxide gas, which are the bubbles you see.
So that explains why the shell disappeared, but what keeps the egg from oozing everywhere?
Just under the eggshell is another type of covering called a membrane. A membrane is sort of like a thin skin. The vinegar doesn't affect the membrane, so it remains intact and holds the egg together. Pretty cool, right?
WHAT'S GOING ON?
Did your egg in the water get big? Did your egg in the corn syrup get small?
Wow! Why did that happen?
Well, first, let's talk about that skin-like membrane of the egg. This thin layer actually has tiny holes in it, which allow for certain things to move in or out.
Picture a fence with holes in it. You might be able to push a tennis ball through, but a basketball wouldn't fit.
In a similar way, small water molecules can move through the egg's membrane, but the larger sugar molecules in the corn syrup cannot fit through the tiny holes.
This helps explain why the egg in the plain water glass grew larger. The concentration of water is higher in the glass than inside the egg. This means that water molecules move from the glass through the membrane into the egg - making it bigger!
In the corn syrup glass, the concentration of water is higher inside the egg than in the corn syrup. This means that the water molecules move out of the egg, through the membrane, into the corn syrup. And the egg shrinks!
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For more exciting experiments, check out our Yellow Scope science kits on the Shop tab of our website!