Physics 215 - Experiment 1
Measurement, Random Error & Err or analys is
Advanced reading- from Physics by Giancoli, 6th Edition
(Sections 1-4, 1-5 & 1-6)
Part A-Measurement of Length and Error Analysis
Equipment:
1 Ruler
1 Vernier Caliper
1 Micrometer Caliper
Several Coins.
Objective:
The object of this experiment is
twofold:
1. To learn to measure lengths
using a ruler, vernier caliper,
and micrometer caliper.
2. To become acquainted with
types of error and statistical
methods for analyzing one's
data and for estimating its ac-
curacy.
3. To determine the density of a
block of metal.
Theory:
In using a ruler three things
must be remembered: (1) the
reading should be estimated to
one half of the smallest division;
(2) the ends of the ruler should
not be used since the ends may
have become damaged and no
longer be square; (3) errors of
parallax should be avoided by
placing the scale against the ob-
ject to be measured.
In using a vernier caliper
tenths of a division are not esti-
mated; they are read off the
vernier scale. Notice that 10 divi-
sions on the vernier scale corre-
sponds to 9 divisions on the main
scale. Therefore, the mark on the
vernier scale which best lines up
with a mark on the main scale
gives the reading of a tenth of
the smallest division on the main
scale (see fig. 1. 1).
Figure 1-1
In using a micrometer caliper,
centimeters and tenths of a cen-
timeter are read from the scale on
the barrel. Then thousandths of
a centimeter are read from the
scale on the thimble. Since this
scale only goes from 0 to 50 thou-
sandths the thimble must be
turned twice to move one-tenth of
