Download Microscopes I - Sewanhaka Central High School District

DO NOW:
Explain this
cartoon in your
own words
Microscopes
Microscopy is the art of
producing images for
microscopic things
that are not visible to the
human eye.
Robert Hooke's microscope (1665)
The first useful microscope
was developed in the
Netherlands in
the early 1600s
1. Compound Light
Microscope
•
Models found in most schools,
uses compound lenses and light
to magnify objects. The lenses
bend or refract the light, which
makes the object beneath them
appear closer.
2. Stereoscope –
this microscope allows for binocular
(two eyes) viewing of larger
specimens.
Polychaete worm (aquatic)
Parasite that causes
disease in your
liver!
3. Scanning Electron
Microscope –
allow scientists to view a universe
too small to be seen with a light
microscope. SEMs do not use light
waves; they use electrons
4. Transmission
Electron
Microscope
also uses electrons, but
instead of scanning the
surface (as with SEM's)
electrons are passed through
very thin specimens.
Due to the
powerful laser
beam, anything
living would die!
A mosquito
An ant
Threaded needle
Scales of a
moth wing
Stinger of a mosquito
DO NOW:
Hand-out
Parts of a
Compound
light
microscope
The structure of a cell nucleus
would be seen in the greatest
detail by use of
1.
2.
3.
4.
a compound light microscope
an ultracentrifuge
a dissecting microscope
an electron microscope
Which is the correct sequence of historical
developments leading to our present
knowledge of cells?
1.
2.
3.
4.
electron microscope – cell theory – compound
light microscope
compound light microscope – cell theory –
electron microscope
cell theory – electron microscope – compound
light microscope
electron microscope – compound light
microscope – cell theory
Bodytube
Eyepiece/
ocular
nosepiece
Objective lens
Objective lens
Objective lens
Stage clips
Diaphragm
arm
stage
Coarse adj.knob
Fine adj. knob
Light source
base
Eyepiece (Ocular lens):
magnifies the image 10x
Stage Clips
& Objectives
(4x, 10x & 40x magnification)
Objective lens
Attached to the
nosepiece
Usually three
magnifications
Examples: 4X, 10X,
40X
Referred to as low
and high powers
Low power objective =
used to locate the
specimen on the slide
Larger field of view (See
more of the slide, but less
details)
High power objective =
More magnification
Smaller field of view but
more details
Deer Tick 41X Magnification
Deer Tick 164X Magnification
Deer Tick 657X Magnification
Used to adjust
the amount of
light entering
the scope
Located
beneath the
stage
Coarse (big) and Fine (small)
adjustment knobs
ARM
Remember!!
ALWAYS
USE TWO HANDS
TO CARRY THE
MICROSCOPE!!!
1.)
Diaphragm
2.
3.
4
.
5
5.
Which structure is best
observed using a compound
light microscope?
1.
2.
3.
4.
a cell
a virus
a DNA sequence
the inner surface of a
mitochondrion
After switching from the highpower to the low-power
objective lens of a compound
light microscope, the area of
the low-power field will appear
1.
2.
3.
4.
larger and brighter
smaller and brighter
larger and darker
smaller and darker
•Is numeric
value that
quantifies how
much a
specimen has
been
magnified.
•Is calculated
by multiplying
the eyepiece
power (usually
10x) by the
objective lens
in place.
magnification that can be
obtained using the microscope
shown?
1.
2.
3.
4.
20x
200x
40x
800x
Total magnification:
Ocular
X
(eyepiece)
Ex.)
Objective
=
total
magnification
Objective
lens
4x
10x
43x
Total
magnification
When viewed with a compound light
microscope under low power, the letter
"p" will appear as
1.
2.
3.
4.
q
p
d
b
How have microscopes
impacted science?
THE END