In this slide show i reviewed about the History,Basic principle, Parts and Use of the Compound microscope

1. THREE GOALS:
•produce a magnified image of the specimen,
•separate the details in the image,
•render the details visible to the human eye or
camera.

2. The History
• Hans and Zacharias Janssen of Holland
in the 1590’s created the “first”
compound microscope
• Anthony van Leeuwenhoek and Robert
Hooke made improvements by working
on the lenses
Anthony van Leeuwenhoek Hooke Microscope Robert Hooke
1632-1723 1635-1703

3. The History
Zacharias Jansen The “First” Microscope
1588-1631

4. Types of microscopes
 Light microscopes
 Bright field microscope
 Dark field microscope
 Phase contrast microscope
 Fluorescent microscope
 Electron microscopes
 Transmission electron microscope
 Scanning electron microscope

5. Magnification
• To determine your magnification…you
just multiply the ocular lens by the
objective lens
• Ocular 10x Objective 40x:10 x 40 =
400 So the object is 400 times “larger”
Objective Lens have
their magnification
written on them.
Ocular lenses usually magnifies by 10x

6. RESOLVING POWER/
RESOLUTION
• ability of a lens to separate or distinguish
small objects that are close together
• wavelength of light used is major factor in
resolution
shorter wavelength ⇒ greater resolution
Actual What We Might See

7. WAVE LENGTH
• Wave length of light – used for
illumination
– Visible range – 400 – 750nm
(Shorter wave length – high resolution)
E.g. Blue light has a shorter wave length
than red light

8. NUMERIAL APERTURE
• NA – of the objectives (property of lens
that decides the quantity of light enter
into it)
– Two factors 1) Refractive Index 2)Angle

9. REFRACTION
• The bending of light as it passes from one
medium to another of different density
• The bending of the light ray gives rise to
an angle of refraction, the degree of
bending
• Index of refraction: A measure of the
speed at which light passes through the
material

10. ILLUMINATION
• To collect and reflect the light – two
devices – 1) Mirror 2) artificial Light
• 1) Mirror – natural source or artificial
source
– Two side – reflective- plain – artificial light
– Concave – natural source

11. Properties of Light:Light & Objects
• Reflection: If the light strikes an
object and bounces back (giving the
object color)
• Transmission: The passage of light
through an object
• Absorption: The light rays neither
pass through nor bounce off an
object but are taken up by the object

13. OIL IMMERSION

14. Ocular Lens
Body Tube
Nose Piece
Arm
Objective
Lenses
Stage
Stage
Clips
Coarse Adj.
Diaphragm Fine Adjustment
Light Source
Base
The Parts of a Microscope

15. Body Tube
• The body tube holds the objective
lenses and the ocular lens at the proper
distance
Diagram

16. Nose Piece
• The Nose Piece holds the objective
lenses and can be turned to increase
the magnification
Diagram

17. Objective Lenses
• The Objective Lenses increase
magnification (usually from 10x to 40x)
Diagram

18. Lenses
• focus light rays at a
specific place called the
focal point
• distance between center
of lens and focal point is
the focal length
• strength of lens related
to focal length
– short focal length ⇒more
magnification
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Companies, Inc.

19. Stage Clips
• These 2 clips hold the slide/specimen in
place on the stage.
Diagram

20. Diaphragm
• The Diaphragm controls the amount of
light on the slide/specimen
Turn to let more light in or to
make dimmer.
Diagram

21. Light Source
• Projects light upwards through the
diaphragm, the specimen and the
lenses
• Some have lights, others have mirrors
where you must move the mirror to
reflect light
Diagram

22. Ocular Lens/Eyepiece
• Magnifies the specimen image
Diagram

23. Arm
• Used to support the microscope when
carried. Holds the body tube, nose
piece and objective lenses
Diagram

24. Stage
• Supports the slide/specimen
Diagram

25. Coarse Adjustment Knob
• Moves the stage up and down (quickly)
for focusing your image
Diagram

26. Fine Adjustment Knob
• This knob moves the stage SLIGHTLY
to sharpen the image
Diagram

27. Base
• Supports the microscope
Diagram

28. How a Microscope Works
Convex Lenses are
curved glass used to
make microscopes
(and glasses etc.)
Convex Lenses bend
light and focus it in
one spot.

29. How a Microscope Works
Ocular Lens Objective Lens
(Magnifies Image) (Gathers Light,
Magnifies
And Focuses Image
Body Tube Inside Body Tube)
(Image Focuses)
•Bending Light: The objective (bottom) convex lens
magnifies and focuses (bends) the image inside the
body tube and the ocular convex (top) lens of a
microscope magnifies it (again).

30. Caring for a Microscope
• Clean only with a soft cloth/tissue
• Make sure it’s on a flat surface
• Don’t bang it
• Carry it with 2 HANDS…one on the arm
and the other on the base

31. Carry a Microscope
Correctly

32. Using a Microscope
• Start on the lowest magnification
• Don’t use the coarse adjustment knob
on high magnification…you’ll break the
slide!!!
• Place slide on stage and lock clips
• Adjust light source (if it’s a mirror…don’t
stand in front of it!)
• Use fine adjustment to focus

33. I. Dark field contrast microscopy takes advantage of
objects that “scatter” light - this requires a special
condenser that can “angle” the incident light
II. Phase contrast microscopy takes advantage of
objects that alter the phase of incident light - This
requires “phase rings” in the condenser and in the
objective lens
III. Fluorescence microscopy take advantage of
inherently fluorescent Material of biological
objected that can be fluorescenlty labeled.

34. DARK FIELD MICROSCOPE
Contrast
Bright Field
Phase Contrast Dark-Field

35. Dark field contrast microscopy
takes advantage of objects that
“scatter” light - this requires a
special condenser that can
“angle” the incident light

36. FLUORESCENT MICROSCOPE
Optical System of a Fluorescein
Fluorescence -excited by blue
Microscope light (450-490)
-emits green
light (520-560)

37. [INSERT FIGURE 4.9]
Fluorescence microscopy take advantage of inherently
fluorescent Material of biological objected that can be
fluorescenlty labeled.

38. Microscopy
[INSERT FIGURE 4.10]

39. Applications of different
microscopes
 Bright field – Stained slides
 Dark field – Live unstained cells
 Fluorescent – Microbiological material