Calibrating - from powerpoint

Question 1

What can you use to measure how large a cell or organelle is?

Answer 1

An eyepiece graticule

Question 2

What is an eyepiece graticule?

Answer 2

It is like a little rule in the eyepiece of a microscope.

Question 3

Why does a graticule need to be calibrated for each magnification?

Answer 3

As the magnification of the objective lens increases the graticule does not get larger.

Question 4

How can an eyepiece graticule be calibrated?

Answer 4

Using a stage micrometer (a little ruler put onto the stage)

Question 5

How do you use an eyepiece graticule?

Answer 5

1) Line up the eyepiece graticule and the stage micrometer
2) Length of 1 eyepiece division = Distance on SM/ Number of divisions on EP
3) Eye piece has now been calibrated
4) Remove stage micrometer and replace with slide.
5) Line interesting object up with eyepiece graticule
6) Object length = Number of divisions on eyepiece graticule X length of 1 eyepiece division.