DENPEN
a superPLAYCHEM experiment
DENSITY of PENNIES
There is a.................... TUTORIAL
There is a.................... PRELAB
There is a.................... VIDEO (83 MB)
Return to................... SYLLABUS

Density = Weight/Volume

DENSITY is a intrinsic property of all matter. It is the ratio of mass to volume.  It is an intensive property, so for homogeneous matter, each portion has the same density as the whole.

In this experiment you will determine the density of a penny by weighing one or more pennies and then dividing this mass by the total volume of the penny (or pennies).

Masses will be measured using a Balance.

  • For a single penny, you will use an Analytical Balance which measures to 4 decimal places in grams.
  • For weighing 8, 10 or more pennies, you will use a Top-Loading Balance which weighs to 2 or 3 decimal places, again in grams.

Volume will be determined in two ways.

1) By measuring the diameter with a ruler and approximating the thickness of a penny, you can calculate its volume using geometry.

V= pr2t = (3.1416)r2t

2) By measuring the volume of water displaced by a number of coins. You can do this by adding a given volume of water to a graduated cylinder, adding the pennies and remeasuring the new volume. Since pennies are not soluble in water, they displace their own volume.

Metals can be differentiated by their Density. After you and your fellow students finish your measurements, you should be able to determine the composition of a new U.S. penny. You should also learn something about the change in composition of a penny over the last three decades.

DENSITIES of some METALS

Aluminum 2.70 g/cc
Copper 8.92 g/cc
Iron 7.86 g/cc
Lead 11.34 g/cc
Zinc 7.13 g/cc

For typical student weight vs date measurements, see the.......PENNY-DATE GRAPH

R.W. Kluiber 1/14/2000