Measurement

Question

can density be calculated or measured and how?

Answer

Density is mass per unit volume.&nbsp; Now mass is weight corrected for gravity, measured in kilograms in the metric system.&nbsp; Volume is measured in cubic meters in the metric system.&nbsp;&nbsp;Thus, density is in units of kilograms per cubic meter.&nbsp;&nbsp;<BR><BR>Oh -- here's a good anecdote about calculating density:<BR><BR>Mass is easy enough to get -- just put the object on a scale.&nbsp; However, volume is not.&nbsp; The volume of a rectangular prism is length times width times height, but what about an oddly shaped object -- like a crown?<BR><BR>Archimedes had a similar problem -- he had to figure out if King Hiero's crown was pure gold.&nbsp; He could weigh the crown easily enough -- but the crown was so oddly shaped, he could not figure out how to get the volume.&nbsp; According to legend, he filled his bathtub up to the top, got in, and water spilled out on the floor.&nbsp; Then it came to him -- all he had to do was take a tub of known volume large enough to hold the crown (maybe a rectangular prism), fill it with water to the top, insert the crown, remove the crown, and then figure out how much water came out.&nbsp; He went out into the city without any clothes on and cried, "Eureka!"&nbsp; (Greek for "I have found it!")<BR><BR><BR><BR>Joe&nbsp;M.<BR>Forest Inventory and Analysis<BR>Knoxville, TN&nbsp;&nbsp; http://vrd.askvrd.org/services/answerschema.xml