Aim: How do we study cells?
MICROSCOPE
I.
Compound Light Microscope (optical microscope)
 Uses light to produce an enlarged view of object
 Uses 2 lenses
 One lens produce an enlarged image & is further magnified by the
second lens
 Lenses cause light rays to bend producing an enlarged image
 Made up of 3 systems: optical, mechanical and light.
Image: what we see when we use a microscope to examine an object
Magnification: the ratio of image size to object size
1.Optical System: the lenses
 Eyepiece (ocular)
 Objectives:
 Low power objective - used to locate the region of the specimen
 High power objective - moved into position if further
magnification is wanted
2. Mechanical System: Structural parts that hold the specimen and
lenses and permit focusing of the image
Base: Support the microscope
Arm: Used to hold the microscope
Stage: Platform on which specimen is placed
Stage clips: Hold the slide in place
Body tube: Holds lenses- eyepiece on top and objectives on the
bottom
Revolving nosepiece: Holds the objective lenses; rotates so that
different objective lenses can be moved
Coarse adjustment: Large knob used for approximate focusing under
LOW POWER only
Fine adjustment: Small knob; final focusing of low power and all
focusing under high power.
3.
Light System:
 Mirror and Substage illuminator: directs light up through the
specimen
 Diaphragm: Regulates the amount of light reaching the specimen
Total Magnification:
Ocular
x
Objective = Total Magnification
(10x)
(43x) =
430x
The greater the magnification, the smaller the field of vision of the
specimen.
RESOLUTION:
 Sharpness of image
 The ability of a microscope to show 2 points that are close
together as separate images
What does the microscope do to the image?
It makes the image UPSIDE DOWN and REVERSED
e
Low Power
Vs.
Less detail
Field is brighter
Image smaller
Field of view is bigger
High Power
More detail
Field is darker
Image larger
Field of view is smaller