PASCO SE-9076 Constant Velocity Tubes - Manual (Page 12)

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Constant Velocity Tubes 012–06697B
c) Now calculate the slope (don’t forget the units):
➤ Your answer should be approximately 13.4 g/ml. You should not
expect to get exactly this answer.
d) Now substitute this value for slope (m) in the formula:
➤ This equation allows us to calculate the mass reading that would result
if some other volume of mercury were tried. Using algebra to solve for
volume, we can also obtain an equation that tells us what volume of mercury
to use to cause some particular mass reading.
14. Solve the equation for volume. Ask for help if you need it.
➤ The original equation would be much more useful if it could apply to
other substances besides mercury as well as containers other than the one
that was used in this experiment. Often, reasoning allows us to adapt an
equation to other purposes.
15. Look at your graph and see if you can express in words the meaning of the y-intercept. (Not
the mathematical meaning, but rather some aspect of the experiment that this value represents.
Hint: What is the volume, at the y-intercept?)
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16. Does the value of the slope remind you of anything? How about the units? Hint: use a
reference to look up the physical properties of mercury. Keep in mind that the numerical
value we obtained by experiment will not be exact.
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17. Finally, the mass reading from the pan balance might better be called gross mass, which is
the mass of both the container and the contents. The preceding ideas can be used to rewrite
the equation into a more generally useful form:
Gross Mass = Density of Contents * Volume of Contents + Mass of Container
slope = rise
run =
y
2
– y
1
x
2
– x
1
=