1. Ocular lens (10x)- the magnifying lens closest to your eye.
2. Body Tube - holds the lenses the proper distance apart.
3. Revolving Nose Piece - holds the objective lens and allows objectives to be rotated for differing magnifications.
4. Objectives are the lenses closest to the object (specimen).
5. Scanning objective (4x) is lowest power and shortest. Used to locate portion of specimen to observe.
6. Low power objective (10x) - the middle length lens.
7. High power objective (40x)- the longest length lens.
8. Stage - supports the object (specimen).
9. Stage Clips hold the object slides in place.
10. Mirror - reflects light upwards through the slide.
11. Substage Illuminator/light - shines light upwards through the slide.
12. Base - supports the microscope.
13. Diaphragm - controls the amount of light striking the slide.
14. Arm/Neck - supports the body tube.
15. Coarse adjustment knob - used to focus with scan objective.
16. Fine adjustment knob - used to focus on low or high power objective.

C. Procedure for using a Microscope

1. Carry microscope with two hands, one on the arm the other on the base.
2. With the arm towards you, place the microscope about 4" from the edge of desk/lab bench. Make sure power cords will not catch on the user or passersby.
3. Verify the scanning objective lens is in place and that the stage is a greatest distance from the scan lens.
4. Look into ocular eyepiece; clean the lenses, mirrors or condenser if needed with lens paper.
5. Place slide over hole in stage and secure with stage clips.
6. Looking from the side, use the coarse adjust knob to bring the stage closest to the scan lens.
7. Looking into the ocular, slowly increase the distance between the slide and the scan lens until the specimen is in focus.
8. Locate area of specimen you wish to view.
9. Slowly rotate nose piece until the low power lens clicks into place.
10. On low and high power objectives, always use the fine adjustment knob, never use the coarse adjustment knob.
11. Observe and sketch the specimen. To reduce eye strain, keep both eyes open.
12. Never allow the objective lenses to contact a slide or specimen. If you must use the coarse adjust start again at step 6.
13. When finished, rotate the scan objective into place.
14. Use the coarse adjustment knob to drop the stage and remove the slide.
15. Bring the body tube to an upright position and wrap the cord around the base.
16. Return the microscope.

D. Properties of a Microscope

1. The objective lenses of compound microscopes are parfocal. You do not need to refocus when switching to a higher power if the object is in focus on a lower power.

2. The field of view is largest on the lowest power objective. When you switch to a higher power, the field of view is reduced. You will see more of an object on low power.  Therefore, it is best to find an object on low power, and then switch to higher power.

3. The depth of focus is greatest on the lowest power objective. Each time you switch to a higher power, the depth of focus is reduced. Therefore a smaller part of the specimen is in focus at higher power. Again, this makes it easier to find an object on low power, and then switch to higher power after it is in focus.

4. The amount of light transmitted to your eye is greatest at the low power. When you switch to a higher power, light (and therefore resolving power, or the ability to distinguish two nearby objects as separate) is reduced. Compensate with the light control (sometimes called the iris).

When drawing what you see under the microscope, follow the format shown below. It is important to include a figure label and a subject title above the image. The species name (and common name if there is one) and the magnification at which you were viewing the object should be written below the image. All relevant parts of the drawing should be labeled on the right side of the image using straight lines. Lines should not cross. Drawings should be done in pencil, while labels should be in pen or typed. Remember that total magnification is determined by multiplying the ocular x objective.

1. Start by rotating the objective lens to lowest power.

2. Place a slide on the stage, label side up, with the coverslip centered.

3. On LOW POWER ONLY, use the coarse focus knob to get the object into focus.

4. If you cannot see anything, move the slide slightly while viewing and focusing.

5. If nothing appears, reduce the light and repeat step 4.

6. Once in focus on low power, center the object of interest by moving the slide.

7. Rotate the objective to the medium power and adjust the fine focus only.

8. If needed, rotate the objective to the high power and adjust fine focus only.