Can an ordinary egg support the weight of a 30 pound cement block? That was the question that Jeff and Joe, two of our Team members, were investigating this past Saturday in the Science Studio. They discovered that a single egg is not up to the task of supporting the brick. It just made a big mess on the bottom of the brick when it was crushed. (Actually, a visitor at the Science Studio insisted we try just one egg to see what would happen.)
So the question is how many eggs would you need to support the brick? After cracking a number of eggs in the name of science, the smallest number of eggs they could get to support a block was eight. Check out the video to see how they did it.
Of course this is really all about force and pressure. A typical cement block weighs about 30 pounds. One egg can’t support 30 pounds. However, if you spread that weight out over eight eggs then each egg is only supporting 30/8 = 3.75 pounds. Apparently an egg can support that much with out being crushed.
In the video below Jeff and Joe carefully arrange 12 eggs to avoid any high spots and take suggestions from the visitors on how to best arrange the eggs and place the brick on top. They were later able to support the brick with just eight eggs.
The whole idea of spreading the weight out over a larger area gets to the idea of pressure, or force per area. In this case we’re talking about the force per egg. It’s very similar to the bed-of-nails demonstration we do from time to time. We have a bed-of-nails with 400 nails that a Team member will lay on. They can lay on them safely because their weight is spread out over all the nails. A bed-of-NAIL (meaning just a single nail) would be very dangerous. A two hundred pound person laying on our bed would have their weight distributed over 400 nails so each nail would be pressing with a force of 200/400 = 0.5 pounds. Not enough force to pierce the skin.
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