MEASUREMENTS BY VERNIER CALIPERS
EXPERIMENT NO. 1
Aims:
1. To understand and get familiar with the use of the Vernier Calipers.
2. To measure the diameter of a small spherical /cylindrical body.
3. To measure the length, width and height of the given rectangular block.
4. To measure the internal diameter and depth of a given beaker/calorimeter and hence find its
volume.
Apparatus:
Vernier Calipers, 1meter rule, Pendulum bob, rectangular block, calorimeter
Theory:
Vernier calipers are used to make more accurate measurements as compared to the meter scale.
However, the procedure for using the Vernier caliper has to be followed carefully in order for the
correct measurement to be made. It is first important to get familiar with the main parts of the
Vernier calipers as illustrated in the figure below.
Figure 1.1
The main scale consists of a steel metallic strip graduated in centimeters at one edge and
in inches at the other edge . It carries the inner and outer measuring jaws. When the two
jaws are in contact, the zero of the main scale and the zero of the Vernier scale should
coincide. If both the zeros do not coincide, there will be a positive or negative zero error.
1. Vernier Scale
A Vernier scale slides on the strip. It can be fixed in any position by the retainer. On the
Vernier scale, 0.9 cm is divided into ten equal parts.
2. Outer Measuring Jaws
The outer measuring jaws help to take the outer dimension of an object
3. Inner Measuring Jaws
The inner measuring jaws help to take the inner dimension of an object.
4. Retainer
The retainer helps to retain the object within the jaws of the Vernier calipers.
5. Depth Measuring Prong
The depth measuring prong helps to measure the depth of an object.
Procedure:
I. Determining Least Count
To determine the least count of the particular Vernier, check the number of divisions on the
Vernier scale. The number of divisions on the vernier scale vary from one another depending on
the desired accuracy by the Vernier caliper. The least count or the smallest reading which you
can get with the instrument can be calculated as;
Least count = one main scale division (MSD) - one Vernier scale division (VSD)
Then the least count is
LC =1MSD - 1VSD
If the nth division of Vernier scale coincides with any division of the main scale, then the
Vernier scale reading (VSR) is;
VSR = n x LC
Then the total reading (TR),
TR = MSR + (VSR x LC)
II. Determining Zero Error (ZE)
In order to determine the zero error and the Vernier scale coincide, then, there is no zero error. If
the Vernier zero lies on the right side of the main scale zero, then the there is no ZE. If the
Vernier zero lies on the right scale of the main scale zero, then the error is positive. The Vernier
division coinciding with any MSD is noted as the ZE and it is to be subtracted from the observed
VSD. If the Vernier zero lies on the left side of the main scale zero, the error is negative and the
result has to be added to the observed VSD at the end.
To find the zero correction of the Vernier scale, if it is the error is negative, the Zero correction
is.
Zero correction = – (zero error)
Zero correction is added algebraically in the observed diameter to get the corrected diameter.
III. Determine the diameter of the Beaker /Calorimeter
1. To measure the internal diameter of the calorimeter, place the Vernier calipers with the
upper jaws inside the calorimeter as shown in the diagram (Fig. 1.1).
2. The upper jaws of the Vernier calipers should firmly touch the ends of a diameter of the
calorimeter, but without deforming the calorimeter.
3. Note the main scale reading immediately before the zero mark of the Vernier and also
note the division of the Vernier which coincides with any of the main scale divisions.
4. Repeat the measurements at least five times and record them.
IV. Determine the depth of the Calorimeter
1. To determine the depth of the calorimeter, let the end of the Vernier Calipers stand on its
end on a glass slab, push down its depth gauge (the central moving strip), so that it also
firmly touches the glass slab. Then note the zero error of its depth gauge.
2. Next, set the Vernier calipers with its end resting on the upper edge of the calorimeter
and its depth gauge touching the bottom inside. Thus note the observed depth of the
calorimeter. Calculated corrected depth by applying zero correction
3. Repeat the measurements at least five times and record them.
V. Determine Volume of a Beaker or Calorimeter
To determine the volume of the beaker or Calorimeter
By using the inner part of the jaws, determine the internal diameter of the calorimeter/beaker.
Also determine the depth calorimeter/beaker using the depth measuring prong.
The volume of a cylinder is given by the relation
where d = internal diameter of cylinder
r = internal radius of the cylinder
h = depth of cylinder
VI Verification
In order to verify the capacity of the beaker or calorimeter measured by Vernier calipers, fill it
completely with water.
Pour this water in to an empty graduated cylinder and observe the volume of this water.
Both values should be in agreement within experimental error.
OBSERVATIONS
I Determine the Least Count
One small division of main scale = ......................... mm
.......... VS divisions = ................ MS divisions
1 VS division = ................ MS divisions
= ................ mm
Least count = 1MS div – 1 VS div
= ................ mm ................ mm
= ................ mm
= ................ cm
II Determine the Zero Error of the Diameter
Zero error for diameter measurement = (1) ........... cm (2) .............. cm (3) ........... cm
Mean zero error = ................ cm
Mean zero correction = – (Mean zero error) = ................ mm
III Diameter of the Beaker/ Calorimeter
SI. No
Main
Scale Vernier Scale Vernier Scale Correct
Vernier Vernier
Reading
Division
Reading
Scale Reading =
(MSR)
(VSD)
VSR =
(MSR +VSR)
VSD x LC
Mean diameter =………………………………..cm
Diameter of the specimen =………………………………..cm
Caliper
ZC
Reading =
MSR + VSR
IV Determine the Depth of the Beaker/Calorimeter
SI. No
Main
Scale Vernier Scale Vernier Scale Correct
Vernier Vernier
Reading
Division
Reading
Scale Reading =
(MSR)
(VSD)
VSR =
(MSR +VSR)
Caliper
ZC
VSD x LC
Reading =
MSR + VSR
Mean diameter =………………………………..cm
Diameter of the specimen =………………………………..cm
Verification
Volume of Beaker/calorimeter as measured by graduated cylinder = ……….. cm3
The internal diameter of the beaker/calorimeter = …………………………cm
The depth of the beaker/calorimeter =…………………………..cm
The volume of the beaker or calorimeter = ………………………………….. cm3.
Internal volume of cylinder
Questions;
1. What other method can you use to determine the diameter of the sphere other than
the one above?
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2. How can you reduce the errors in this experiment?
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