[Unit 3.3] | Microscopic Measurements & Calculations

Question 1

What is an eyepiece graticule?

Answer 1

• A glass disc 10mm long with a 100 subdivision scale.

• Can be used to measure the size of objects under a microscope’s lens.

Question 2

How do you calibrate an eye-piece graticule?

Answer 2

• Place a stage micrometer under the microscope’s lens & compare the units.
• If one unit on the micrometer is 10um, and 4 eye-piece units = 1, then each epu is 2.5um.

• This allows you to determine the size of each unit on the eye-piece graticule under different magnifications.