3.3 Microscope measurements and calculations

Question 1

What is an eyepiece graticule?

Answer 1

a glass disc that is placed in the eyepiece of a microscope, with a scale etched on it (usually 10mm long and divided into 100 subdivisions)

Question 2

What is a stage micrometer?

Answer 2

a glass slide placed on the stage, with a scale etched onto it (usually 2mm long, with 0.01mm subdivisions)

Question 3

How can you calibrate a eyepiece graticule with a stage micrometer?

Answer 3

Using the micrometer, see how many units on it are equivalent to those on the graticule (e.g. 1 micrometer units : 4 graticule units)
Find the unit value on the micrometer (e.g. 0.01mm) and divide the equivalent graticle units by that to find the value of the micrometer units at that magnification
–>Different objective lenses can use that value to calibrate the graticule unit value