Experiment 1

 Measurement and Density

Objectives:

To measure the mass densities of a few regular-shaped solid objects

 Equipment:

This is the only experiment that you need to use a fairly sensitive scale (at least to 1 gram precision) and a metric ruler (usually good to 1 mm precision). The use of an electronic mass scale and a dial caliper is preferred if you have access to one or both.  In experiment 2, you will need a 30.0-cm Metric ruler and a protractor.  All other experiments will be done online.

Theory: 

           Measurement devices have limited precisions that must be considered during use.  These limited precisions will result in the transmission and compounding of errors if the correct significant figures are not applied to calculations.  The student should have an understanding of significant figures prior to this experimentFor a brief on significant figures click on the following link:  significant figures.

 Mass density is defined as the mass per unit volume.  gm/cm3 is, therefore, a unit of mass density.  The mass density ρ of an object may be found by dividing its mass M by its volume V.

Formulas used in the calculation of volume (V) are:

Rectangular block or cube:  V = length x width x height  = LWH

            Sphere V = (4/3) π R3   where R is the radius of the sphere.

Cylinder:  V = π R2L   where R is the radius of its base and L the length of it.

Mass densities of a few substances are given below:

Table 1

Aluminum     2.7 gm/cm3 Ice        0.9 gm/cm3  Brass      8.6 gm/cm3
Concrete      2.3 gm/cm3 Iron      7.8 gm/cm Lead     11.3 gm/cm3
Copper         8.9 gm/cm3 Steel     7.8 gm/cm3 Gold     19.3 gm/cm3

Procedure:

 

 

 

Figure 1

Data:

Device

Sensitivity

Zero

Ruler or Dial Caliper

   

Mass Scale

   

I)  The rectangular block (Use a Metric ruler)

Trial

 

Length (cm) Width (cm) Thickness (cm) Mass (gram)
1        
2        
3        
Mean        

Table 1

II) The cylinder or sphere (Use a dial caliper if available)

Trial

 

 Diameter (cm)

of Cylinder or Sphere

Length (cm)

for Cylinder Only

Mass (gram)

of Cylinder or Sphere

1      
2      
3      
Mean      

Table 2

Calculation(s):

 

Provide the necessary calculations.

Comparison of the results: 

Use the percent error formula given above to calculate a percent error for each material, if the material used is listed above.

Conclusion: 

State your conclusions of the experiment.

Discussion: