Measurement.micrometer & vernier caliper

1. Presented by:
Riel M. Casinillo
Faculty
MeasurementMeasurement
and Measuring Devicesand Measuring Devices
(Micrometer and Vernier Caliper)(Micrometer and Vernier Caliper)

2. What are we going to do today?What are we going to do today?
1) We are going to read and use the following 1) We are going to read and use the following
instruments in measuring certain quantities:instruments in measuring certain quantities:
MicrometerMicrometer
Vernier CaliperVernier Caliper

3. The MicrometerThe Micrometer
A A micrometermicrometer allows a measurement of the size of a allows a measurement of the size of a
body. It is one of the most accurate mechanical body. It is one of the most accurate mechanical
devices in common use.devices in common use.
Parts of a Micrometer

4. How to read and use the How to read and use the
Micrometer?Micrometer?

5. • The line labeled 0 is the primary pointer. When it lines up
with the central horizontal line on the cylinder, as shown,
then the distance between the measuring rods is exactly an
integral or half-integral number of millimeters.
•The left-hand side of the thimble has markings all around it.
3) In this case, then, the distance between the measuring rods
is 7.000 mm. The upward line on the cylinder
corresponding to 7 mm is barely visible under the thimble.
Primary
pointer
Central horizontal line
1234 6
7
0.5
1.5
2.5
3.5
4.5
5.5
6.5

6. Remember!!!Remember!!!
Report to 3 decimal places. Your instrument is Report to 3 decimal places. Your instrument is
capable of reading up to thousandths of a capable of reading up to thousandths of a
millimeter. ( That is why it is called a millimeter. ( That is why it is called a
micrometer, 10micrometer, 10
-6 -6
of a meter).of a meter).

7. 1) If we rotate the thimble one complete revolution so it
moves to the right, it will look as shown.
2) Now the distance between the measuring rods is
7.500 mm. The downward line on the cylinder
corresponding to 7.5 mm is barely visible.
3) Note that this is all consistent with the fact that the
markings on the cylinder correspond to fifty divisions for a
complete revolution. Thus the numbers on the thimble
correspond to hundredths of a millimeter.
7
7.5
7.5+0.000 = 7.500 mm

8. One more complete revolution takes the One more complete revolution takes the
distance to distance to 8.0008.000 mm, as shown. mm, as shown.
8
0.000
8.000 mm + 0.000 mm = 8.000 mm

9. Now turn the thimble just a little bit more, and end up Now turn the thimble just a little bit more, and end up
with the situation shown.with the situation shown.
We have increased the distance by 0.120 mm from We have increased the distance by 0.120 mm from
8.000, so the distance between the measuring rods is 8.000, so the distance between the measuring rods is
now now 8.1208.120 mm. mm.
8
0.120 mm
8.000 mm + 0.120 mm = 8.120 mm

10. If we give the thimble one complete further rotation, If we give the thimble one complete further rotation,
we end up with the micrometer as shown above.we end up with the micrometer as shown above.
Now the distance is 0.120 mm greater than Now the distance is 0.120 mm greater than 8.5008.500
mm, so the distance is mm, so the distance is 8.6208.620 mm. mm.
8.5 mm
0.120 mm
8.500 mm + 0.120 mm = 8.620 mm

11. Finally, if we turn the thimble a tiny bit further, it Finally, if we turn the thimble a tiny bit further, it
might end up like the figure above.might end up like the figure above.
Now the distance is greater than 8.620 mm, but Now the distance is greater than 8.620 mm, but
clearly less than 8.630 mm. We might estimate this clearly less than 8.630 mm. We might estimate this
reading to be reading to be 8.6248.624 mm. mm.
8.5 mm
0.120 mm
8.500 mm + 0.124 mm = 8.624 mm

12. Depending on your eyes and screen resolution, you Depending on your eyes and screen resolution, you
might be fairly confident that the reading is less than, might be fairly confident that the reading is less than,
say, 8.627 mm and similarly confident that it is greater say, 8.627 mm and similarly confident that it is greater
than 8.621 mm. Thus you might assign a than 8.621 mm. Thus you might assign a Reading Reading
ErrorError to this measurement of 0.003 mm to this measurement of 0.003 mm
So, we would report the distance as So, we would report the distance as 8.624 ± 0.0038.624 ± 0.003
mm. mm.

13. Let us try!!!Let us try!!!

14. 1)
Answer: 7.880 mm

15. 2)
Answer: 7.721± 0.003 mm

16. 3)
Answer: 3.560 mm

17. 4)
Answer: 5.801 ± 0.003 mm

18. 5)
Answer: 3.090 mm

19. Zero errorZero error

20. The Vernier CaliperThe Vernier Caliper
This instrument may be used to measure outer This instrument may be used to measure outer
dimensions of objects (using the main jaws), dimensions of objects (using the main jaws),
inside dimensions (using the smaller jaws at the inside dimensions (using the smaller jaws at the
top), and depths (using the stem). top), and depths (using the stem).

21. How to read and use the How to read and use the
Vernier Caliper?Vernier Caliper?

22. The reading here is 3.7 mm or 0.37 cm.

23. The reading here is 15.8 mm or 1.58 cm.

24. In figure 4 above, the first significant figures are taken as the
main scale reading to the left of the vernier zero, i.e. 3.7 cm.
The remaining digits are taken from the vernier scale reading
that lines up with any main scale reading, (i.e. 0.46 mm or
0.046 cm) on the vernier scale. Thus the reading is 3.746 cm.

25. In figure above, the first significant figures are taken as the
main scale reading to the left of the vernier zero, i.e. 3.4 cm.
The remaining digit is taken from the vernier scale reading that
lines up with any main scale reading, (i.e. 0.60 mm or 0.060
cm) on the vernier scale. Therefore the reading is 3.460 cm.

26. In figure 6 the zero and the ten on the vernier scale
both line up with main scale readings, therefore the
reading is 4.000 cm.

27. Let us try!!!Let us try!!!

28. 1)
Answer: 3.090 cm

29. Answer: 0.810 cm
2)

30. 3)
Answer: 12.168 cm

31. Zero ErrorZero Error

32. Okay, that is enough!Okay, that is enough!
Let us try to apply it in Let us try to apply it in
real life.real life.

33. Try to measure the quantities of the Try to measure the quantities of the
following objects. Fill-out the table following objects. Fill-out the table
below.below.
Quantities to Quantities to
MeasureMeasure
MicrometerMicrometer Vernier CaliperVernier Caliper
1) Diameter of a 1) Diameter of a
1-peso coin1-peso coin
2) Thickness of a 2) Thickness of a
5-peso coin5-peso coin
3) Thickness of 3) Thickness of
your hairyour hair

34. Give me a reading of:Give me a reading of:
5.66 cm5.66 cm
4.78 cm4.78 cm