Living Environment Translated Arabic 2014 | Page 18

2. How to focus a microscope
a. Plug in and turn on the microscope
b. Using the coarse adjustment knob move the stage all the
way UP
c. Place the slide on the stage and secure it with the stage
clips
d. Move the low power objective into place.
e. Look into the eyepiece and SLOWLY move the stage down
until the image comes into focus using the coarse
adjustment knob
f. Use the fine adjustment knob to bring the image into
sharper focus if necessary.
g. KEEP BOTH EYES OPEN!!!!!!!
h. Adjust the diaphragm if more or less light is needed.
3. Under low power more cells appear in the field of view but
there is limited detail.
4. Under high power fewer cells appear in the field of view but
the viewer can see much greater detail.
5. A stain is often used to see more detail in cells.
6. To calculate the magnification of a microscope, multiply the
power of the eyepiece by the power of the objective lens.
a. Low power magnification = 4 X 10= 40 x ( 40 times larger
than normal)
b. High power magnification= 10X 10= 100X ( 100 times larger
than normal)
7. To calculate cell size:
a. Determine the size of the field of view
b. Count the number of cells in one row across the diameter
of the field of view
c. Use the following formula: Cell size= field of view
Number of cells