Learning Outcomes
Candidates should be able to:
(f) describe how to measure a variety of lengths with appropriate accuracy by means of tapes, rules, micrometers and calipers, using a vernier as necessary.
Length
Length can be measured using micrometers, vernier calipers, rulers and measuring tapes.
|
Length to be measured |
Example |
Instrument to be used |
|
Long length (several metres) |
Length of the classroom |
Measuring tape |
|
Medium length (10 cm to 1 m) |
Length of pendulum |
Metre rule |
|
Short length (1 cm to 10 cm) |
External diameter of a test tube |
Vernier calipers |
|
Very short length (less than 2.5 cm) |
Diameter of a wire |
Micrometer screw gauge |
Accuracy of the measuring instruments
|
Instrument |
Accuracy |
|
Rulers and measuring tape |
1 mm, 0.1 cm |
|
Vernier calipers |
0.1 mm, 0.01 cm |
|
Micrometer screw gauge |
0.01 mm, 0.001 cm |
Use vernier calipers to measure short lengths. Click on vernier calipers to view a java applet application to see how to use it.
A screen capture of the java applet in action
Background: A pair of vernier calipers can measure up to 10 cm (laboratory use) or 25 cm (engineering use). To read off the actual reading, sum the reading in the main scale (indicated in blue) and the vernier scale (indicated in green).
Use micrometer screw gauge to measure short lengths. Click on micrometer screw gauge to view a java applet application to see how to use it.
A screen capture of the java applet in action
Background: A pair of vernier calipers can measure up to 2.5 cm (laboratory use). To read off the actual reading, sum the reading on the sleeve (indicated in blue) and the thimble(indicated in green).
Click here to have a better understanding of how to use the vernier calipers and micrometers. Also try to do all the exercises in the page and check the answers on your own by clicking the answers. If you have any queries and doubts, do not hesitate to seek your teacher immediately.
To know more about zero errors. Click on zero errors to download the word document from my alma mater, NUS. Pay attention in the class to know more about it.
Click here to read more about how to use these measuring devices properly.
