1. Microscopes

2. Care for your microscope
Always carry your scope with 2 hands (One around the handle/Arm; One supporting the base)
The Handle/Arm and oculars should be facing you when using the microscope.
Only use lens paper to clean the objectives. (provided in each Student Drawer)
Store the dust cover in your drawer/cabinet so it is out of the way
Always use the plastic mat provided under your microscope

3. Types of Microscopes
Light microscope – uses visible light to see stuff
Simple microscope – one set of lenses (dissecting microscope)
Compound microscope (two sets of lenses (ocular, objective)
Imaging techniques
Darkfield and phase contrast – see unstained samples based on denser structures
Staining – used to color specific structures and identify specific subject
Fluorescent – use invisible light to generate color (better contrast)
Confocal microscopy – constrain field of view and move the stage around to see the whole image clearly
Electron microscope – uses electrons to see stuff
Scanning electron microscope – what bounces off of 3-dimensional subject
Transmission electron microscope – what passes through a sliced sample

4. REVIEW! - Microscope focusing
Initial Focusing
Use Slide #3: Bacteria and Blood
Place slide between stage clips, label facing up (coverslip OVER slide)
Turn on the light until you have a WHITE background. (CONDENSER should be all the way up)
View the slide through the OCULARS with both eyes. (adjust the for the distance between your eyes until you are able to see one field of vision)
Use the STAGE ADJUSTMENT KNOBS until the specimen is in the middle of the light.
Use the COURSE FOCUS to bring the specimen into focus. Start with the stage all the way DOWN (this is how the stage needs to be stored) and turn the coarse adjustment knob AWAY from you.

5. How to see your sample (better!)
Improve the contrast
Seeing difference between desired object and its neighbors (air, irrelevant cell etc.)
Which image to the right has better contrast?
Improved with fluorescence, staining, darkfield and phase contrast microscopy
Improve the resolution
Use of higher-power magnifications
Use of bluer lightsources
short wavelength/high energy
Shorter wavelength allows one to see finer details
Spread your sample out better
Improve the intensity
Increase amount of light entering the sample
useful for high-power when light diffused
Oil immersion – oil concentrates light, allowing more light to enter the objective lens
Diaphragm ; increases light, but tightens focus

6. Moving to the next higher magnification (10x)
Parfocal: the specimen will be in partial focus when moving to the next higher magnification; only need to adjust with FINE FOCUS with each magnification increase or decrease
Move the revolving nosepiece clockwise to the next objective (Low Power-10X)
Once specimen is into focus, you can move to the next higher objective (40x) by repeating the above steps
Use only the FINE FOCUS for High-Power (40x) and higher
magnifications to bring the specimen into focus
Using the course focus at this time will damage the objective as it crashes into your microscope slide)

7. Calculating total magnification
Compound microscopes use both objective lenses and ocular lenses
Total magnification – ocular mag. × objective mag.
Example: 40x objective and 10x ocular
40x × 10x = 400x total magnification
Which Objective was used if a 25x ocular gave a total magnification of 2500x?

8. Care of the Microscope
The High-Dry/HighPower objective (40X) is to NEVER touch oil.
Same with the 4X and 10X objective lenses
The oil will damage the lens and you will not be able to see anything clearly

9. Oil Immersion
Once your specimen is brought to focus under the High-Dry, you can use Immersion oil for the oil objective ONLY.
Move the revolving nosepiece to the scanning objective (40x→10x→4x). This gets the lenses out of the way
DO NOT lower the stage. The stage and lighting is set for the best view of the specimen already. You worked hard to get to this stage!
Add a drop of immersion oil onto the slide where light is passing through
Rotate the revolving nosepiece counterclockwise (4x→100x) and adjust the focus using ONLY the FINE FOCUS.
You may need to adjust the diaphragm to allow more light to pass

10. Storing your Microscope
Scanning Objective (4X) over the Stage
Oil Immersion Objective COMPLETELY wiped clean of oil (with lens paper!)
Center the stage
Stage in the full down position
Scope switched off
Phase Adapter in the OUT position
Cord Wrapped around cord holder
Dust Cover on
Microscopes are stored with the handle facing out
Clean up mat and put it away