LAB #2: Density
Theory:
Define density and write down an equation. What is volume? Write down equations for
volume of the strip and cylinder.
What is the difference between instrumental and statistical uncertainty; when to use one
and when another?
Experiment:
•
•
•
Determine the mass for both objects, using the digital balance (don't forget about
the uncertainty for the measuring device)
For the cylinder, measure its diameter 10 times using digital caliper and height
once using caliper (don’t forget about corresponding uncertainties: statistical for
the diameter and instrumental for height)
For the strip, measure the length once using ruler (instrumental uncertainty),
width once using caliper (instrumental uncertainty), and thickness 10 times using
micrometer (statistical uncertainty)
Calculations:
• Calculate average diameter of the cylinder and average thickness of the strip
along with their statistical uncertainties.
• Calculate the volume for the cylinder and the strip and corresponding
uncertainties (VC ± δVC & VS ± δVS)
• Calculate the density for the cylinder and the strip (ρC ± δρC & ρ S ± δρS
• Compare the density values for each object with those in the table - do any of
the table values matches your values, within the uncertainty of your
measurements? This means that the following should be true:
X −Y
δX + δY
<3
We require that X and Y are less than 3 standard deviations apart. If so then X and Y
agree with each other within the uncertainty.