1. Microscopes

2. Types of Microscopes Light Microscopes (compound and dissecting)
Advantages
Can look at living things
See in color
Requires simple preparation
Fairly inexpensive

3. There will be a quiz on this picture and your lab!
Disadvantages
Specimens must be thin.
Limited magnification (~2,000X)
Resolution is poor on higher magnifications
What is resolution?
Read page 847 in your textbook, then draw and label the picture of a compound microscope
There will be a quiz on this picture and your lab!

4. Transmission & Scanning Electron Microscopes
Advantages
Greater magnification (scanning 100,000 X and transmission 200,000 X)
Scanning EM will give you a 3-D view
Scanning EM
Transmission EM

5. 2. Disadvantages
Can only look at dead things.
Specimen preparation is time consuming and expensive.
Objects appear black and white.
Very expensive.

6. What type of microscope took this picture?

7. What kind of microscope took this picture?

8. What type of microscope was used to take both of these pictures?

9. How to use the microscope
Carrying the microscope
Always use 2 hands; one on the arm and one on the base.
Don’t tilt or swing the microscope because the eyepiece may fall out.

10. Setting up the microscope
Place microscope on a flat, even surface, about 3-5 inches from the edge of the table.
Unwrap cord and plug into the nearest outlet.
Use lens paper only to clean eyepiece and objectives.
Use paper towels to clean slides and any non-glass parts.
Place the microscope slide on the stage and secure it with the metal clips.

11. Using the microscope Always begin… Nosepiece lowered all the way down
On lowest/scanning objective (4X)
Eyepiece set to 10X
Diaphragm set to 1 or 2 (controls amount of light)
Nosepiece lowered all the way down
While looking through the eyepiece, move the slide back and forth, or side to side until you locate a blurry object.
Use the coarse adjustment knob to center and focus on the blurry object.

12. Switch to next higher power objective; center and focus again
Switch to next higher power objective; center and focus again. Adjust light if necessary.
If image isn’t clear enough repeat steps 1- 4 going to the highest magnification.
Never use coarse adjustment (large knob) while on high power or you may break or scratch the lens.
Switch back to scanning objective before you remove slide.

13. Putting away the microscope
Make sure objective is set to scanning (4x)
Clean and dry stage, slide and cover-slip.
Remove the plug from the socket (don’t pull on the cord), wrap up the cord, not too tight or it will break out of the base of the scope.
Lower the eyepiece, so it’s all the way down.

14. Magnification and Field of View