Archimedes' Principle

Archimedes was asked by King Hiero II to determine if the crown made for the

King was composed of pure gold. Because he could not damage the crown,

Archimedes had to find a way to determine its composition. He used the

displacement method to find the crown's volume and then measured the

crown's mass to determine the density. Because density is a physical property

that does not change, Archimedes could determine if the density of the crown

was equal to the density of gold. The densities did not match, so he was able to

determine that the crown was not made from pure gold.

Determine density using the calculation method.

a. Remove the string from the magnet, dry the magnet, and place the magnet

directly on the scale. Record the magnet's mass in grams in Data Table 6.

b. The magnet is a regular-sized, three-dimensional object with a measurable

length, width, and height. Use a metric ruler to measure these dimensions.

c. Calculate the magnet's volume. Use the equation: volume equals length x

width x height. For example: 1 cm x 1 cm x ½ cm = 0.5 cm3. Record this value

under column B – A in Data Table 6.

d. Use the mass and the volume measurements to calculate the magnet's

density. Record this value in Data Table 6.

Density: The density of a substance is its mass per unit