MicroscopesMicroscopes

I.I. Types of MicroscopesTypes of MicroscopesA.A. Light Microscopes (compound and Light Microscopes (compound and

dissecting)dissecting)1.1. AdvantagesAdvantages

a.a. Can look at living thingsCan look at living thingsb.b. See in colorSee in colorc.c. Requires simple preparationRequires simple preparationd.d. Fairly inexpensiveFairly inexpensive

2.2. DisadvantagesDisadvantages

a.a. Specimens must be thin.Specimens must be thin.

b.b. Limited magnification (~2,000X)Limited magnification (~2,000X)

c.c. ResolutionResolution is poor on higher is poor on higher magnificationsmagnifications

What is resolution?What is resolution? Read page 847 in your textbook, then draw Read page 847 in your textbook, then draw

and label the picture of a compound and label the picture of a compound microscopemicroscope

There will be a quiz on this picture and your lab!There will be a quiz on this picture and your lab!

B.B. Transmission & Scanning Transmission & Scanning Electron MicroscopesElectron Microscopes

1.1. AdvantagesAdvantages

a.a. Greater magnification (scanning 100,000 X Greater magnification (scanning 100,000 X and transmission 200,000 X)and transmission 200,000 X)

b.b. Scanning EM will give you a 3-D viewScanning EM will give you a 3-D view

Transmission EM Scanning EM

2. Disadvantages2. Disadvantagesa.a. Can only look at dead things.Can only look at dead things.b.b. Specimen preparation is time Specimen preparation is time

consuming and expensive.consuming and expensive.c.c. Objects appear black and white.Objects appear black and white.d.d. Very expensive.Very expensive.

What type of microscope What type of microscope took this picture?took this picture?

What kind of What kind of microscope took this microscope took this

picture?picture?

What type of microscope What type of microscope was used to take both of was used to take both of

these pictures?these pictures?

II.II. How to use the How to use the microscopemicroscope

A.A. Carrying the microscopeCarrying the microscope

1.1. Always use 2 hands; one on the arm and Always use 2 hands; one on the arm and one on the base.one on the base.

2.2. Don’t tilt or swing the microscope Don’t tilt or swing the microscope because the eyepiece may fall out.because the eyepiece may fall out.

B.B. Setting up the microscopeSetting up the microscope1.1. Place microscope on a flat, even surface, Place microscope on a flat, even surface,

about 3-5 inches from the edge of the table.about 3-5 inches from the edge of the table.

2.2. Unwrap cord and plug into the nearest Unwrap cord and plug into the nearest outlet.outlet.

3.3. Use Use lenslens paperpaper onlyonly to clean eyepiece and to clean eyepiece and objectives.objectives.

4.4. Use paper towels to clean slides and any Use paper towels to clean slides and any non-glass partsnon-glass parts..

5.5. Place the microscope slide on the stage and Place the microscope slide on the stage and secure it with the metal clips.secure it with the metal clips.

C.C. Using the microscopeUsing the microscope1.1. Always begin…Always begin…

a.a. On On lowest/scanning objectivelowest/scanning objective (4X) (4X)

b.b. EyepieceEyepiece set to 10X set to 10X

c.c. DiaphragmDiaphragm set to 1 or 2 (controls amount set to 1 or 2 (controls amount of light)of light)

d.d. Nosepiece Nosepiece lowered all the way downlowered all the way downa.a. While looking through the eyepiece, move While looking through the eyepiece, move

the slide back and forth, or side to side the slide back and forth, or side to side until you locate a blurry object.until you locate a blurry object.

b.b. Use the Use the coarse adjustment coarse adjustment knob to knob to centercenter and and focusfocus on the blurry object. on the blurry object.

4.4. Switch to next higher power objective; Switch to next higher power objective; center and focus again. center and focus again. Adjust light if Adjust light if necessary.necessary.

5.5. If image isn’t clear enough repeat steps 1- If image isn’t clear enough repeat steps 1- 4 going to the highest magnification.4 going to the highest magnification.

Never use coarse adjustment (large Never use coarse adjustment (large knob) while on high power or you may knob) while on high power or you may break or scratch the lens.break or scratch the lens.

6.6. Switch back to scanning objectiveSwitch back to scanning objective before you remove slide.before you remove slide.

D.D. Putting away the microscopePutting away the microscope1.1. Make sure objective is set to scanning (4x)Make sure objective is set to scanning (4x)

2.2. Clean and dry stage, slide and cover-slip.Clean and dry stage, slide and cover-slip.

3.3. Remove the plug from the socket (don’t pull Remove the plug from the socket (don’t pull on the cord), wrap up the cord, not too tight on the cord), wrap up the cord, not too tight or it will break out of the base of the scope.or it will break out of the base of the scope.

4.4. Lower the eyepiece, so it’s all the way down.Lower the eyepiece, so it’s all the way down.

Magnification and Field of ViewMagnification and Field of View