Pressure (cont'd)

Let's do some math! The pressure exerted by the nail over a small area will be much larger than that exerted by block #1. Feel free to use the calculator below!

Block #1:
weighs 50 pounds & pushed down on the table over an area of 2 square feet.The formula for finding the pressure on table #1 is: 50 pounds divided by 2 square feet, which equals 25 pounds per square foot... then divide 25 pounds by 144 inches (the number of inches in a square foot) and you'll arrrive at 0.173 pounds per square inch

Block #2:
weighs 50 pounds & pushed down on the nail, the nail pushed down on the table over an area of .01 square inches. The formula for this is: 50 pounds divided by .01 square inches, which equals 5,000 pounds per square inch!!!

Can you see why the nail punched a hole through the wood?

This example simply illustrates the difference between pressure and weight. Pressure is measured over a given area. Weight does not change, no matter what size of an area it is placed upon.