10 mL Graduated Cylinder
Step 1: Determine the scale increment
To find the scale increment, subtract the values of any two
adjacent labeled graduations and divide by the number of intervals
between them. In the 10 mL graduated cylinder above, first subtract
8 mL - 6 mL = 2 mL. Next, count that there are ten intervals between
the labeled graduations. Therefore, the scale increment is 2
mL/10 graduations = 0.2 mL/graduation.
Step 2: Use the graduations to find all certain digits
Use the labeled graduations and the scale increment to find
the certain digits in the measurement. The first digit is 6, since
the last labeled graduation below the meniscus is six. Next, use
the scale increment. There are three unlabeled graduations below
the meniscus, and each graduation represents 0.2 mL, for an additional 0.6 mL. Therefore, the certain digits of the reading are 6.6 mL.
Step 3: Estimate the uncertain digit and obtain a reading
Estimate the distance that the meniscus lies between the two
graduations as a decimal fraction and multiply by the scale increment.
Above, the meniscus is about one tenth of the way to the next
graduation, so the final digit in the reading is (0.1 increment)
* (0.2 mL/increment) = 0.02 mL. The uncertain reading is added
to the certain digits, so the volume measurement is 6.62 mL.
Copyright © 1995-1996 NT Curriculum Project, UW-Madison