MEASUREMENTS

When you measure the length in inches with a meterstick, you record the even number(larger division, that is, the number before decimal point)first, then record the number of next subdivisions(there are eight subdivisions), finally estimate the fraction of the smallest subdivision. For example, you get even number 6, second number is 7, you estimate that the measurement takes 1/3 of the smallest division. You record as
              (6 + 7 x 1/8 + 1/3 x 1/8) in.
Convert into decimal you get
             [6 + 7 x (0.125) + (0.33) x (0.125)]inches = 6.9166in.
Taking two significant figures, we have
              6.92in.

Tips for using Vernier Caliper and Micrometer Caliper

Vernier Caliper

1. Find the position of index of the Vernier scale on the main scale, record that number, including the larger and smaller divisions e.g. you get 21mm;
2. Find the first even number on the vernier scale which aligns with the main scale, record this number, e.g. you get 5;
3. Count the number of the lines which immediately follow the the even number and better align with the main scale, e.g. you get 2; (you can also get 0, if so, record this 0.)
4. The measurement is 21mm + 0.5mm + 0.02 x 2mm = 21.54mm;
5. If the last number you get is 0, you record as: 21mm + 0.5mm + 0.02 x0mm = 21.50mm. Do not ignore the last 0.

Micrometer Caliper

1. Record the mark on the frame scale, and be sure whether you see the bottom scale or not, e.g. you record 12mm;
2. Record the number on the cylinder, e.g. you get 32. If you do not see the bottom scale, your measurement is 12.32mm. If you see the bottom scale, you record 12mm + 0.32mm + 0.50mm = 12.82mm.