Types of Microscopes
Compound
Description
Costs
Source of Radiation
for Image Formation
Medium
Compound microscopes are
light illuminated. The image
seen with this type of
microscope is two
dimensional. This
microscope is the most
commonly used. You can
view individual cells, even
living ones. It has high
magnification. However, it
has a low resolution.
$150 - $10,000
Dissection or
Stereoscope
Scanning Tunnel Microscope
This microscope uses a needle-like
A dissection microscope probe to measure differences in voltage
is light illuminated. The caused by electrons that leak, or tunnel,
image that appears is
from the surface of the object being
three dimensional. It is
viewed. A computer tracts the
used for dissection to get
movement of the object across the
a better look at the larger object, enabling objects as small as
specimen. You cannot see individual atoms to be viewed. The
individual cells because it computer creates a 3-D image of the
has a low magnification. specimen’s surface. It can be used to
study living organisms.
$20,000-100,000
$100-$1500
Scanning Electron
Microscope (SEM)
Transmission Electron
Microscope (TEM)
SEM use electron
illumination. The image is
TEM is electron
seen in 3-D. It has high
illuminated. This gives a 2magnification and high
D view. Thin slices of
resolution. The specimen is specimen are obtained. The
coated in gold and the
electron beams pass through
electrons bounce off to give
this. It has high
you an exterior view of the
magnification and high
specimen. The pictures are
resolution.
in black and white.
more than $50.000
more than $50,000
visible light
visible light
electrons
electrons
electrons
air
air
vacuum
vacuum
vacuum
Specimen mounting
glass slides
none
Ceramic positioning device
Nature of Lenses
glass
glass
Probe
Focusing
mechanical
mechanical
digital computer
Magnification
Adjustments
changing objectives
usually 1 objective
digitally enhanced
Major Means of
Providing specimen
Contrast
Light Absorption
light scattering or light
reflection
Voltage differences
Images
Thin films of collodion or
Mounted on aluminum stubs
other supporting material on
and are coated in gold
copper grids
one electrostatic lens with a one electrostatic lens and a
few electromagnetic lenses few electromagnetic lenses
Electrical i.e. current of the
objective lens coil is
electrical
changed.
Electrical i.e. changing
electrical
current of the projector lens
coil
electron scattering
Electron scattering