Part 1: Finding the Specific Gravity of Aluminum

Archimedes’ Principle Introduction:

The specific gravity of a material is defined as the density of the material divided by the density of water: S.G. =  /water = , where M is mass and V is volume. If the two masses had the same volume, this would reduce to M/Mwater. Now, the buoyancy force of the object in water is equal to the mass of the water displaced (this is Archimedes’ principle) so Mwater = buoyancy force. The volumes are the same because the water displaced has the same volume as the object that displaced it.

Procedure:

Part 1: Finding the specific gravity of aluminum.

1. Measure and record the mass (to within 0.05g) of the aluminum cylinder in air:Mass in

air:______g ______

2. Measure and record the apparent mass of the aluminum cylinder while completely submerged in a beaker of water: Mass in water:______g______

Part 2: Finding the specific gravity of rubbing alcohol.

3. Fill a different beaker with alcohol. Measure and record the apparent mass of the aluminum cylinder while completely submerged in alcohol:

Mass in alcohol:______g______

Part 3: Finding the specific gravity of wood.

4. Measure and record the mass of the wooden cylinder by itself in air:

Mass in air:______g______

5. Attach the lead sinker to the wooden cylinder and weigh the combination of wood and sinker with only the sinker submerged in water:

______g______

6. Measure and record the mass of wood cylinder and sinker together with both wood and sinker submerged in water: ______g______Part 4: Finding the specific gravity of an irregular solid.

7. Perform a measurement to determine the material of the irregular solid, using Archimedes’ Principle. Record your data below. Calculations: Calculate: a) the specific gravity of the aluminum cylinder and the percent error of the result;

S.G.Aluminum = (mass of aluminum in air)  (mass of aluminum in air – mass of aluminum in water)

b) the specific gravity of the alcohol and the percent error of the result;

S.G.Alcohol = (mass of aluminum in air – mass of aluminum in alcohol)  (mass of aluminum in air – mass of aluminum in water)

c) the specific gravity of the wood cylinder and the percent error of the result;

S.G.wood = (mass of wood in air)  (mass of wood in air with lead in water – mass of wood and lead both in water )

d) the specific gravity of the irregular solid and the percent error of the result; e) What was the material of the irregular solid?

Conclusion/Discussion:

1. Describe the purpose of each part of the procedure. 2. Describe how you accomplished the procedure. 3. Describe and evaluate the results. 4. Make a comprehensive list of sources of measurement error in this lab.

In your conclusion, clearly state how Archimedes’ principle is used in this lab.