Syllabus Edition

First teaching 2020

Last exams 2024

|

Measurement Techniques (CIE AS Physics)

Revision Note

Test yourself
Katie M

Author

Katie M

Last updated

Measurement Techniques

  • Common instruments used in Physics are:
    • Metre rules - to measure distance and length
    • Balances - to measure mass
    • Protractors - to measure angles
    • Stopwatches - to measure time
    • Ammeters - to measure current
    • Voltmeters - to measure potential difference

  • More complicated instruments such as the micrometer screw gauge and Vernier calipers can be used to more accurately measure length

 

Measuring Instruments, downloadable AS & A Level Physics revision notes

  • When using measuring instruments like these you need to ensure that you are fully aware of what each division on a scale represents
    • This is known as the resolution

  • The resolution is the smallest change in the physical quantity being measured that results in a change in the reading given by the measuring instrument
  • The smaller the change that can be measured by the instrument, the greater the degree of resolution
  • For example, a standard mercury thermometer has a resolution of 1°C whereas a typical digital thermometer will have a resolution of 0.1°C
    • The digital thermometer has a higher resolution than the mercury thermometer

          Measuring Instruments TableMeasuring Instruments Table, downloadable AS & A Level Physics revision notes

Micrometer Screw Gauge

  • A micrometer, or a micrometer screw gauge, is a tool used for measuring small widths, thicknesses or diameters
    • For example, the diameter of a copper wire

  • It has a resolution of 0.01 mm
  • The micrometer is made up of two scales:
    • The main scale - this is on the sleeve (sometimes called the barrel)
    • The thimble scale - this is a rotating scale on the thimble

  • The spindle and anvil are closed around the object being measured by rotating the ratchet
    • This should be tight enough so the object does not fall out but not so tight that is deformed
    • Never tighten the spindle using the barrel, only using the ratchet. This will reduce the chances of overtightening and zero errors

  • The value measured from the micrometer is read where the thimble scale aligns with the main scale
    • This should always be recorded to 2 decimal places (eg. 1.40 mm not just 1.4 mm)

Micrometer Screw Gauge, downloadable AS & A Level Physics revision notes

How to operate a micrometer

 

Vernier Calipers

  • Vernier calipers are another distance measuring tool that uses a sliding vernier scale
    • They can also be used to measure diameters and thicknesses, just like the micrometer
    • However, they can also measure the length of small objects such as a screw or the depth of a hole

  • Vernier calipers generally have a resolution of 0.1 mm, however, some are as small as 0.02 mm - 0.05 mm
  • The calipers are made up of two scales:
    • The main scale
    • The vernier scale

  • The two upper or lower jaws are clamped around the object
    • The sliding vernier scale will follow this and can be held in place using the locking screw

  • The value measured from the caliper is read when the vernier scale aligns with the main scale
    • This should always be recorded to at least 1 decimal place (eg. 12.1 mm not just 12 mm)

Vernier Calipers, downloadable AS & A Level Physics revision notes

The vernier caliper reading is read when the vernier scale aligns with the main scale

 

You've read 0 of your 10 free revision notes

Unlock more, it's free!

Join the 100,000+ Students that ❤️ Save My Exams

the (exam) results speak for themselves:

Did this page help you?

Katie M

Author: Katie M

Expertise: Physics

Katie has always been passionate about the sciences, and completed a degree in Astrophysics at Sheffield University. She decided that she wanted to inspire other young people, so moved to Bristol to complete a PGCE in Secondary Science. She particularly loves creating fun and absorbing materials to help students achieve their exam potential.