How do I use a microscope?
Your microscope usually has 3 or 4 different objectives. Magnification increases as
the number on the objective increases. This also means that as you increase your magnification, you reduce
the field of view (area which you can see at any one time). In order to focus the microscope you should
start with the smallest objective.
The microscope should provide you with a lever or knob with which you can adjust
the intensity of the light. With a small magnification you need very little light to illuminate the sample.
As the magnification is increased you may need to increase the light as well. Avoid using too much light as
this will make it very difficult to find the sperm cells; they become "washed out" and appear to be absent.
Place your slide with cover-glass so that one edge of the glass is lined up in the
middle of your viewing area. Gently adjust the coarse focus until you see the edge of the glass appear. Use
the fine focus to make this edge appear as clear as possible. Make sure the edge is in the middle of your
viewing area before going up to the next magnification.
When you increase the magnification adjust only the fine focus until the line appears
again. Once you are at the proper magnification, and the edge appears clear, the slide can be moved so that the
sample is in the viewing area. Remember: when you are looking through the microscope you are seeing a mirror
image of the sample. If you wish to move the sample to the left in the viewing area, the slide itself must be
moved to the right.