8. Compound Light Microscope
contains more than one lens
magnification: up to 1000x
useful for studying many kinds of
cells and small organisms
9. Electron Microscope
in the 1920s, a German physicist discovered a way
to use magnets to focus beam of electrons
uses a beam of electrons instead of light to
examine a sample
magnification: as much as 1000x larger than a
light microscope
10. Electron Microscope
Two Kinds:
Transmission Electron
Microscope (TEM)
Scanning Electron
Microscope (SEM)
11. TEM
gives a 2 - D view
works much like a
slide projector
specimen must be
cut into very thin
slices so that the
electron beam can
pass through
12. SEM
gives a 3 - D view
uses a thin beam of
electrons to scan a
sample’s surface
does not reveal the
internal structure of a
sample
14. Terms to remember:
Magnification – ability of the microscope to
magnify or enlarge an object (example:
5x, 10x, 45x)
Total Magnification: magnification of the
eyepiece x magnification of the objective
Resolution = sharpness of an image
16. Parts of the Microscope
Three main parts:
A. Optical Parts
B. Illuminating Parts
C. Mechanical Parts
17. A. Optical Parts
- used for magnification of
the image
1. Ocular / eyepiece
2. Objectives
18. A. Optical Parts
Objectives – tubes attached to the revolving
nosepiece
A. SPO (4x) – gives an overview of the
specimen
B. LPO (10x) – used for locating parts of the
specimen
C. HPO (40x) – use to view small details of
the specimen
19. B. Illuminating Parts
- used to focus or direct light
1. Mirror - used to reflect light
- plane, convex
2. Diaphragm - regulates the amount of
light reflected
20. C. Mechanical Parts
- necessary for movement and
support
1. Base – allows the microscope to stand
2. Pillar – supports the stage
3. Stage – where glass slide is placed
4. Arm – curved part grasped when
carrying the microscope
21. C. Mechanical Parts
5. Revolving nosepiece – where the
objectives are attached
6. Draw tube – holds the eyepiece
7. Coarse adjustment knob – raises or
lowers the body tube to bring image into
focus
8. Fine adjustment knob – focuses image
further
22. C. Mechanical Parts
9. Inclination joint – allows tilting of the
microscope
10. Mirror rack – holds mirror in place
11. Stage clip – holds specimen in place
on the stage