Density of Irregular Solids (Rocks and minerals)

1.     Find the mass of the specimen to the nearest 0.01g.

2.     Tie a length of nylon string around the specimen and make sure you can lift the specimen without dropping it.

3.     Place the overflow can on a ring stand, adjust so that the spout is over a graduated cylinder (try 25 ml to start).

4.     Hold your finger over the overflow spout, then fill the can with water above the spout. Remove your finger and allow the excess to flow into the cylinder. Empty the water and replace the cylinder under the spout.

5.     Hold specimen by string, then lower the specimen into the water. Record the volume of water that flows into the cylinder to the nearest 0.1 ml.

6.     Calculate the mass density (rho). r=mass/volume. The units should be g/cm^3, (1ml = 1 cm³).

7.     Consult the table of standard values and record the accepted value in column 5. In your report, discuss the accuracy and precision of this method. Accuracy refers to the agreement of experimental data with known (literature) values. Precision refers to the agreement between repeated determinations, or in the case of a single measurement, the number of significant figures based on the experimental method.

8.     What is the identity of your unknown based on density? How confident are you of this answer?

9.     Do any rocks or minerals float? Discuss in your report.