The resolving power of the microscope is 0.2 microns.
A micron is a millionth of a meter (10−6 meters).
If a specimen is 0.2 microns or larger, the microscope can see it.
If a specimen is smaller than 0.2 microns, it is invisible to this microscope.
If two cells are at least 0.2 microns apart, they will be seen as two separate cells. If they are closer than 0.2 microns, the microscope will show them as one cell.
Microscope Specifications
Bright field microscope.
Maximum magnification: 1000 times.
Resolving power: 0.2 microns (ability to see small details).
Can see bacteria and larger organisms.
A smaller resolving power would indicate a stronger, better microscope.
Specimens Visible
The microscope is suitable for viewing bacteria, protozoa, fungi, worms, algae, arthropods, and human cells.
Microscope Setup
Microscopes will be located at student tables (two per table).
The power cord is also located inside the student tables.
Leave the dust cover in the cabinet.
Handling the Microscope
Always use two hands to carry the microscope.
Place one hand on the arm and the other under the base.
The microscopes cost at least $2,000 each.
Handle with care.
Cleaning Supplies
Chemwipes will be available in the room.
Lens paper will be available at the tables.
Use either chemwipes or lens paper to clean the microscope.
Cleaning Procedure
Clean the microscope thoroughly before use.
Clean the eyepieces first.
If dirt or oil is present, use alcohol and clean again (do not use glutaraldehyde).
Clean the objective lenses (4x, 10x, 40x, 100x).
If dirt or oil is present, use alcohol and clean again.
Clean the condenser.
If dirt or oil is present, use alcohol and clean again.
Clean the light bulb (lipo).
If dirt or oil is present, use alcohol and clean again.
Microscope Parts
Ocular Lenses (Eyepieces)
Magnification of 10x.
Adjustable to fit individual eyes.
Adjust to see one clear picture, not two separate images.
One eyepiece has a focusing knob to correct for blurry vision in one eye.
Use the focusing knobs to focus the image, one eye is clear, one eye is blurry, you can fix that.
Use the knobs to get right eye focused, the left eye has its own focus.
Arm
Used to carry the microscope.
Revolving Nosepiece
Allows switching between objective lenses.
Objective Lenses
Magnify the image.
Come in powers of 4x, 10x, 40x, and 100x.
Labeled with their magnification.
Only the 100x lens (oil immersion lens) is safe to dip in oil.
If oil gets on other lenses, it can damage the microscope.
Stage
Includes the mechanical stage where the slide is placed.
Slides should be labeled-up.
The stage and mechanical stage hold the slide.
Mechanical Stage Knob
Moves the mechanical stage (and slide) forward, backward, left, and right.
Coarse Adjustment Knob
Large knob used for major/broad focusing.
Fine Focus Knob
Small knob used for fine, precision focusing of the image.
Condenser
Focuses light onto the slide.
Condenser Knob
Used to adjust the height of the condenser.
The condenser should be all the way up.
Iris Diaphragm
Switch on the condenser that adjusts the amount of light coming through.
Typically, it should be all the way open for maximum light.
Illuminator (Light Bulb)
Provides light for viewing the specimen.
Has a light switch (on/off) and a light intensity switch (up/down).
Magnification
Total magnification = (eyepiece magnification) x (objective lens magnification).
Eyepiece magnification = 10x.
Examples:
4x objective: 4 x 10 = 40x total magnification.
10x objective: 10 x 10 = 100x total magnification.
40x objective: 40 x 10 = 400x total magnification.
100x objective: 100 x 10 = 1000x total magnification.
Resolution
Clarity and detail of the image.
Field of View
As magnification increases, the field of view gets smaller.
The microscope zooms in towards the center of the field of view.
Detail
Detail improves as magnification increases.
Working Distance
The space between the objective lens and the slide.
Working distance decreases as magnification increases.
4x objective has the largest working distance.
100x objective has the smallest working distance (almost touching the slide).
Microscope Usage
Plug in the microscope.
Start with the 4x objective (or 10x if struggling).
The stage should be all the way up.
Turn the light on (but not too bright).
Clean the slide with kimwipes or lens paper (and alcohol if needed).
Place the slide on the mechanical stage with the label up.
The specimen should be over the light.
Adjust eyepieces to see one clear picture.
Focusing Procedure
Use the coarse adjustment knob to find the bacteria.
Center the bacteria with the mechanical stage knob.
Use the fine focus knob for fine-tuning.
Adjust the light intensity switch for proper lighting.
If the lighting is poor, check the iris diaphragm and open it all the way.
Once the image is perfect on 4x, move to 10x.
At 10x, focus using the coarse adjustment knob, center the image, and use the fine focus knob.
Once the image is perfect on 10x, move to 40x.
At 40x, only use the fine focus knob.
Keep the bacteria centered using the mechanical stage knob.
100x Objective (Oil Immersion)
The oil prevents the refracting of light on the 100 power lens.
Once the image is perfect on 40x, shift the nosepiece halfway between objectives.
Apply two or three drops of oil directly onto the slide.
Rotate the 100x objective into place so it touches the oil.
Turn up the light intensity.
Focus using the fine focus knob (shadows should improve, not disappear).
Center the bacteria with the mechanical stage knob.
Check the clarity before calling for grading, as the image can blur quickly.
Cleaning After Use
Wipe the oil off the slide using kimwipes (use alcohol if needed).
Wipe the oil off the 100x objective.
Turn off the power.
Return the microscope and power cord to the cabinet.
Return the slide to its proper sleeve.
Troubleshooting
If lost on 100x, go back to 4x or 10x and refocus.
Skip the 40x objective to avoid getting oil on it.
If still struggling, clean everything and start again.