MICROSCOPY
MICROSCOPE
• DEFINE: instrument that produces
enlarged image of object
• Used to study organisms, cells, and
cell parts
• Increase image of object and
• Show object’s details
• MAGNIFICATION: increase of object’s
apparent size
• RESOLUTION: power to show object’s
details clearly
LIGHT MICROSCOPES
• COMPOUND LIGHT MICROSCOPE
(LM)
• To see small organisms and cells
• Specimen must be cut thin enough
so light can pass through and
mounted onto glass slide
• Different set magnifications
LIGHT MICROSCOPE
PARTS OF LM
 STAGE: supports specimen
 LIGHT SOURCE: mirror, light bulb;
directs light upwards, through
specimen
 OBJECTIVE LENS: enlarges
image of object
 NOSEPIECE: holds objective lens
of different magnifications
 OCULAR LENS: near eyepiece;
magnifies image further
 CONDENSER/ DIAPHRAGM: controls the amount of light projected to
specimen
 COARSE FOCUS: focuses object into view
 FINE FOCUS: focuses fine details of object into view
ELECTRON MICROSCOPE
• At about 2000x magnification images
become blurry
• Uses beam of electrons instead of light
to enlarge image of specimen
• Types:
• Transmission Electron
Microscope (TEM)
• Scanning Electron Microscope
(SEM)
Black Walnut Tree Leaf
TRANSMISSION ELECTRON
MICROSCOPE
• Transmits beam of electron
through very thin slice of
specimen
• Magnetic lenses enlarge image
and project it in screen or
photographic plate
• PRO: 200,000x magnification
• CON: Can NOT view living
things
SCANNING ELECTRON
MICROSCOPE
• Provides 3-D images
• Specimen not sliced but
coated with a fine metal
spray
• Electrons bounce off metal
coating and projected onto
fluorescent screen of
photographic plate
• PRO: 100,000x
magnification; 3-D image
• CON: Can NOT be live
specimens
LM VS TEM VS SEM
Diatom, 1000x
Mitochondria, mammalian lung
Fly Head
USING THE COMPOUND LIGHT MICROSCOPE
• WET MOUNT REVIEW
• MOVING THE SLIDE
• LETTER INVERSION
• DEPTH OF FIELD
• MAGNIFICATION
EYEPIECE (10x) x LENS (10X LOW OR 40X HIGH)=100X, 400X
USING THE COMPOUND LIGHT MICROSCOPE
•
MEASUREMENT IN MICROMETERS ( µ )
1mm = 1000 µm and .001mm = 1 µm
•
DIAMETER OF FIELD
EXAMPLE UNDER HIGH POWER
DIAMETER (LOW POWER)= 4 mm
DIAMETER (HIGH POWER)
40/10 = 4
•
4000/4 = 1000 µm
PROPER CARE AND USAGE
MICROSCOPE LAB DIRECTIONS SUMMARY
TEXTBOOK PAGES 691-694
•
NOTES: SEE MATERIAL LIST ON P.691
•
SKIP STEP #’S 19-24
•
REVIEW MICROSCOPE DIAGRAM ON THE TOP LEFT OF P.692 FOR PARTS A AND B
•
YOU DO NOT HAVE TO DO TABLE PC.1
•
FOR PART C, MAKE WET MOUNT SLIDES OF THE LETTERS O, C, AND E AND DRAW WHAT YOU
OBSERVE UNDER LOW OR HIGH POWER (10X OR 40X). KEEP YOUR WET MOUNT OF THE
LETTER “E” FOR #33.
•
NOTICE WHAT HAPPENS TO YOUR SPECIMEN WHEN YOU MOVE THE SLIDE ONE WAY OR THE
OTHER.
•
PAY ATTENTION TO WHAT HAPPENS TO YOUR FIELD OF VIEW WHEN YOU INCREASE
MAGNIFICATION (AS WELL AS IF YOU HAVE TO ADJUST YOUR LIGHT DIAPHRAGM).
•
FOR PART D, USE THE COLORED THREADS SLIDE IN THE BACK OF THE ROOM FOR #25-30.
•
FOR PART E, USE THE TRANSPARENT RULER IN THE BACK OF THE ROOM TO MEASURE
YOUR FIELD OF VIEW USING THE 4X OBJECTIVE LENS (USE mm MARKINGS AND PLACE THE
RULER ON THE FAR LEFT OF YOUR FIELD OF VIEW, MAKE YOUR MEASUREMENT AND THEN
CONVERT IT TO MICROMETERS).
•
FINISH THE LAB BY DOING ANALYSIS QUESTIONS #1-6 ON P.694.
HOW TO USE THE MICROSCOPE
MICROSCOPE QUIZ FORMAT
• 21 M.C. QUESTIONS
• 3 M.C. BONUS QUESTIONS (1 PT. EACH)
• REVIEW: OUTLINE SHEET, LAB ANALYSIS QUESTIONS, STUDY GUIDE
QUESTIONS, MICROSCOPE DIAGRAM p.692