EXPERIMENT NO. 7
The Vernier and Micrometer Calipers
I.
OBJECTIVES
● To learn the proper use of the Vernier and Micrometer Calipers
● To make accurate measurements of short distances using the Vernier and
Micrometer calipers.
II.
THEORY/DISCUSSION
The accuracy of a measurement is always limited by the precision of
the apparatus used and the skill of the Observer in using it. No reading on
an apparatus used in measuring physical quantities is ever exact since a
point is always reached at which the reading becomes uncertain. The last
or final digit of the reading is often just an estimate and, therefore,
doubtful. However, this digit is important because it might significantly
affect the results of the computations.
In linear measurement, the meter stick can be used. But because of the
limited accuracy of the meter stick in measuring small objects, one should
resort to the use of the vernier and micrometer calipers.
III.
MATERIALS
Vernier caliper
Magnifying lens
Micrometer Caliper
Coin
Metal Cylinder
Steel ball
Triple-beam balance
Figure 3. The Vernier Caliper
IV. PROCEDURE
The Vernier Caliper
1. Study the main scale and vernier scale of the vernier caliper. Determine the smallest
main scale and vernier scale divisions, the total number of vernier divisions and the
least count. Close the jaws of the caliper and observe the zero reading.
2. Measure the inside diameter and the depth of the metal cylinder in centimeters and
in inches, adjusting the upper jaws and depth bar accordingly. Record the main scale
and vernier scale readings and get the sum of these two readings to get the diameter.
Compute for the volume of the cylinder in cm3 by substituting the measured values
in these equations:
𝑉𝐶 =
𝜋𝑑2 ℎ
4
or 𝑉𝑐 = 𝜋𝑟 2 ℎ
3. Get the mass of the metal cylinder in grams using the triple-beam balance. Fill the
cylinder with water. Wipe off the excess water at the mouth of the cylinder. Reweigh
the cylinder and its contents on the balance. Compute for the mass of the water in
the cylinder.
4. Using the density of water (= 1 g/cc), compute for the volume of water in cm3.
Compute for the amount of error and percent error using the volume of water as the
true value.
5. Find the relationship between the centimeter and the inch by dividing each
measurement in centimeters by its equivalent in inches for both the measured inside
diameter and depth. Compare the result of your computation with 2.54 cm, which
is the commonly accepted conversion factor. Compute for the amount of error and
percent error.
The Micrometer Caliper
Figure 4. The micrometer caliper
1. Examine the calibrations on the micrometer caliper. Observe and record the zero reading.
2. Open the caliper and clamp the steel ball with the instrument.
3. Get the readings on the horizontal and vertical scales. The sum of the readings obtained
represents the diameter of the steel ball.
4. Make three (3) trials and get the average diameter.
5. Repeat the procedure for the diameter of the coin, then the diameter of the metal rod
V. DATA AND CALCULATIONS
Vernier Caliper Readings
Total number of main scale divisions (s)
Total number of Vernier divisions (f)
Smallest vernier scale division
Least count (slt)
Zero reading
Metric
_____________
_____________
_____________
_____________
_____________
cm
cm
cm
cm
cm
English
_____________
_____________
_____________
_____________
_____________
in
in
in
in
in
Inside diameter of the cylinder
Depth of the cylinder
Mass of the cylinder with water
Mass of the cylinder
Mass of the water
Volume of the cylinder (E,V,)
Volume of the water (T.V.)
Amount of error
Percent error
_____________ cm _____________ in
_____________ cm _____________ in
_____________ g
_____________ g
_____________ g
_____________ 𝑐𝑚3
_____________ 𝑐𝑚3
_____________ 𝑐𝑚3
_____________ %
E. V. of the inside diameter
1 inch
=
__________
Amount of error
=
__________
% error
=
__________
E.V. of the depth
1 inch
Amount of error
% error
(T.V., 1 inch = 2.54 cm)
(T.V., 1 inch = 2.54 cm)
=
=
=
__________
__________
__________
Micrometer Caliper Readings
Trial
1
2
3
Steel Ball
___________ mm
___________ mm
___________ mm
Coin
___________
___________
___________
mm
mm
mm
Metal Rod
___________ mm
___________ mm
___________ mm
Average
___________
___________
mm
___________
Computations
mm
mm
VI. QUESTIONS AND PROBLEMS
1. Give advantages/disadvantages of using the:
a. vernier caliper
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b, micrometer caliper
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2. The following are the obtained values for the depth of the cylinder measured during
three trials: 8.35 cm, 8.36 cm, and 8.33 cm. What is the average depth of the cylinder?
If the inner diameter measured 4.5 cm, what would the volume of the cylinder be?
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3. When measuring small distances, which gives the most accurate measurement: a meter
stick, a vernier caliper or a micrometer caliper? Justify your answer.
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4. The width of a glass plate measures 7.35 cm using a vernier caliper. Which scale the
caliper gives a:
a. 7.0 cm reading?
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b. 0.35 cm reading?
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5. The diameter of a coin is 3.54 mm as read from a micrometer caliper. Which part of
caliper gives a reading of:
a. 3.00 mm?
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b. 0.50 mm?
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c. 0.03 mm?
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VII. CONCLUSION
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VIII. DOCUMENTATION