Calibration

Question 1

Why is Calibration done ?

Answer 1

This procedure is designed so that you can make accurate measurements of specimens or parts of specimens that you wish to view under the microscope

Question 2

The conversion to other magnifications is accomplished by factoring in the difference in magnification.

Answer 2

In the example, the calibration would be 25 µm at 40x, 2.5 µm at 400x, and 1 µm at 1000x.

Question 3

How do you determine the cell density ?

Answer 3

Count only those cells which are fully within a square or are touching the top or left border.

2. Estimate the number of cells in a square.
   Enlargement of middle square
3. Pick the square size that will give you at least 100 cells. There are three sizes of squares: small, medium and large (see table below and figure overleaf).
4. Count the number of cells in that square. If you have fewer than 100, count the cells in another square(s) of the same size until you have a total of >100 cells. Write down the number and size of squares that you count.
5. Calculate the cell density per mL of volume. Remember that: 1 mL = 1 cm3 = 1 mm6

Question 4

What units can the specimen be measured in ?

Answer 4

arbitrary units.

Question 5

Why do you have to use metric units ?

Answer 5

In order to apply a scale bar to a drawing using metric units, you must calibrate the microscope

Question 6

What is Haemocytometer ? and what is used for ?

Answer 6

Instrument used for counting blood cells.