Soil Microbial Ecology - Soil Molecular Ecology Laboratory
Soil Microbial Ecology - Soil Molecular Ecology Laboratory
Soil Microbial Ecology - Soil Molecular Ecology Laboratory
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Page 27<br />
MICROSCOPE OPERATION<br />
Microscope is an expensive and delicate instrument. Replacement cost is about $1800.<br />
Treat it with care! Dropping or jarring it will cause considerable damage.<br />
USE TWO HANDS TO CARRY the microscope as to grab the microscope arm with<br />
one hand and support the microscope base with the other hand.<br />
Gently remove the microscope from its cabinet. Plug the microscope cord into the<br />
electrical outlet on your table. Adjust light setting to give reasonable light<br />
illumination. Higher settings shorten the bulb life; bulb will burn out in 30 minutes.<br />
Recent microscopes have a revolving head to change the direction of the oculars lens<br />
unit. Find the proper interpupillary distance by adjusting the oculars with both hands<br />
until a single image is seen.<br />
Locate the coarse and fine focusing knobs and rotate them back and forth gently<br />
while observing the movement of the objective lenses.<br />
Rotate objective lens and notice that there is a positive click into position for each<br />
lens. Look at the markings on each lens, colored rings, NA, and magnification.<br />
Secure slide on stage with slide clips.<br />
Adjust the condenser under the stage to achieve good resolution.<br />
Put the 4x objective into position and adjust the condenser position to see the light<br />
coverage in the field of view.<br />
Put the 10X objective into position and do adjustments for better view<br />
Move the iris diaphragm lever back and forth for the best amount of light passing<br />
through.<br />
Microscope oculars are focused independently of each other. Compound<br />
microscopes in this laboratory have adjustable left ocular and fixed right ocular.<br />
Close your left eye and bring the object on focus with the fine adjustments. Then<br />
close the right eye and focus the left ocular by turning the focusing ring on the left<br />
ocular tube. Recheck the right eye for proper focus. This should a regular practice<br />
before any microscope use. The main cause of eyestrain and fatigues during<br />
microscope work come from improper focus.<br />
When using oil immersion lens use oil of 1.5 RI then gradually move from 4X, 10X,<br />
45X, and finally 100X. Excessive oil will obscure large portions of the slide from<br />
further examination at lower powers.<br />
READING ASSIGNMENT:<br />
Molling, F. K. 1981. Microscopy from the very beginning. Carl Zeiss, Oberkochen,<br />
West Germany. (copies in 2170 McCarty).
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