What's the formula that would be used to calculate the actual diameter of pollen grain H
Answers
Answer:
There are no scales on our photographs of pollen grains in our Pollen Image Library. These are photographs, not just a picture of the whole field of view of the microscope.
Firstly, a camera does not exactly replace the eye in the microscope system. The microscope is sometimes extended with a tube to fit on the eyepiece of the microscope - or even replace the eyepiece.
Secondly, photographs can be reproduced at different scales to show the detail of the pollen grain. A small grain may be enlarged on the photograph, whereas a large grain may already fill the photo.
You need to be able to measure the size of your pollen grains in your microscope system. Almost every microscope is different!
This can be done in two different ways:-
a) using a "stage micrometer". This is a finely engraved slide which you put on the microscope stage in place of the microscope slide. When you focus on it, you see there is a small ruler which spans the field of view from one side to the other. You can use this ruler to measure the "diameter of the field of view" and record this "fov" measurement for use from there on. This measurement is different if you change either the eyepiece or the objective, but with your x10 eyepiece and your x40 objective, it is a constant value. It is useful if this measurement is converted to micrometres (µm) - 1µm is 1/1000 of a milimetre.
You can then estimate how many pollen grains will fit across the field of view. You may estimate how many would fit in half the field of view (the radius) and double the value. Divide that number into the fov and you have the size of your pollen grain.
b) using an "eyepiece micrometer". This is a
transparent film or glass disc which fits into the eyepiece just below the top lens. This lens will unscrew and the eyepiece micrometer will rest on the black ring part way down the eyepiece tube. The eyepiece micrometer remains in position all the time and you will see a ruler superimposed on your view of pollen grains.