Concrete block smashed on lecturer's chest with sledge hammer.
What it shows:
The lecturer (or someone else) lies on a bed-of-nails without discomfort, thus demonstrating the concept of pressure, which is the force per unit area. For added drama the person is sandwiched between two beds of nails with the added weight of a cinder block on top. The cinder block can be broken with a sledge hammer.
How it works:
The forces (weight of the body, cinder block, etc.) are distributed over the total area of all the nail...
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