BREAK AN EGG  more experiments

Materials:

raw egg

clear zip-up baggie

Directions:  Place the egg inside the baggie and zip it up very carefully!  Now place the egg in the palm of your hand and try squeezing as hard as you can with your entire hand.  Can you break the egg?  Now try squeezing the egg between your palm and just one finger.  What happens now?  Under normal circumstances, you will not be able to break the egg with your whole hand, but you can with one finger!

NOTE: Be careful when working with raw eggs.  Raw eggs sometimes contain salmonella, which is a bacteria that can make you very sick.  So if you get raw egg on your hands, be sure to wash them!

Science:  Eggs are incredibly strong.  If you look carefully, you will see that they look a lot like a three-dimensional arch, which is one of the strongest shapes used to build buildings.  The curve in the shell distributes pressure all over the shell evenly.  So when pressure is applied evenly, the egg can withstand enormous amounts of pressure.  But, if pressure is applied unevenly (with just one finger, for example) the egg easily cracks.  (This would also be true if you squeeze the egg while wearing a ring -- the ring will provide enough uneven pressure to break the egg!)

Weird Fact:  You can tell a hard-boiled egg from a raw egg by spinning them both.  The hard-boiled egg will spin more easily than a raw egg. This is because in the raw egg, the insides are sloshing around which causes the egg to spin less efficiently as its center of gravity continually moves.  But a hardboiled egg is a solid with a center of gravity that does not move -- this allows it to spin very efficiently.