Physics Labs for Scientists and Engineers - Mechanics Worksheet Lab 1-1
Measurements - Density of a Cylinder
As you work through the steps in the lab procedure, record your experimental values and the results
on this worksheet. Use the exact values you record for your data to make later calculations.
Data
You will practice taking some dimensional measurements and use them to determine the density of
a cylinder made of an unknown material.
Record the number written on the end of your cylinder.
Record the mass of the cylinder.
Measure the length of the cylinder with the Vernier calipers. See Measuring with Vernier Calipers
if you’re not sure how to read the calipers.
Copyright
© 2013 Advanced Instructional Systems, Inc. and NC State University Physics Department
Physics Labs for Scientists and Engineers - Mechanics Worksheet Lab 1-2
It is common practice to attempt to obtain a more accurate value of a measured quantity by making
many measurements and then averaging them together. You will do this with the diameter of the
cylinder to obtain a better value. Measure the diameter at a number of places along the cylinder‘s
length, and average. Record the readings for the cylinder’s diameter in the table below.
Table 1
Reading
Diameter (m)
D1
D2
D3
D4
D5
D6
D7
D8
Calculations
As a reminder, this is the equation for the volume of a cylinder.
V = πr2 L
In this equation, r is the radius of the cylinder and L is its length. (This is easy to remember
if you think about slicing the cylinder into circular slices. Each slice has area πr2 and the slices
run all along the length L.) For any object, its density ρ is defined as
ρ=
m
,
V
the ratio of the object’s mass to its volume.
Copyright
© 2013 Advanced Instructional Systems, Inc. and NC State University Physics Department
Physics Labs for Scientists and Engineers - Mechanics Worksheet Lab 1-3
Calculate the average value for the diameter of the cylinder.
What is the experimental value for the density of the cylinder?
Use the Table of Densities to answer the following questions.
Table of Densities
Which of the following materials are consistent with your calculations? (Your value is consistent if
within 20% of the theoretical value. Select all that apply. Note: the order of these options may be
different in the WebAssign question.)
ˆ aluminum
ˆ iron
ˆ copper
ˆ none of these
How far away from that material’s given density is your value? Enter the percent error of your
value. (Use the Table of Densities to calculate your answer. If more than one material is consistent
with your experimental density, use the most consistent material to calculate your percent error.
If an answer does not exist, enter DNE.)
Copyright
© 2013 Advanced Instructional Systems, Inc. and NC State University Physics Department
Physics Labs for Scientists and Engineers - Mechanics Worksheet Lab 1-4
Analysis
During the lab, did you notice that at the ends of the cylinder the edges are not sharp, but slightly
rounded off? This means that it was not a perfect cylinder as we assumed. How does this affect
your calculated value for the density of the material? Explain.
Copyright
© 2013 Advanced Instructional Systems, Inc. and NC State University Physics Department