Transcript Microscope Basics

T. Trimpe 2005
http://sciencespot.net/
Base
-Single
piece
of metal
-Support here
when moving
Arm
-Hold here
when moving
Stage
-Supports
specimen
-Hole allows
light to pass
through
Diaphragm
-controls
amount of
light
-ranges 1-5
Stage Clips
-secures
specimen/slide
Bulb/Mirror
-Light source
-NEVER use
the sunlight it
will hurt your
eyes!!
Scanning Objective Lens
-Shortest lens
• 4x
magnification
Low Power Objective Lens
- Medium
length lens
• 10x
magnification
High Power Objective Lens
-Longest lens
• 40x
magnification
Body Tube
-Allows light
from
objective to
pass upward
Eye Piece/Ocular lens
-Site of
observation
• 10x
magnification
Nose Piece
-Allows you to
switch objective
lenses
Coarse Adjustment Knob
-Used to focus
specimen
-DO NOT use on
high power
objective lens
Fine Adjustment Knob
-Used for minute
focusing
-Used after
coarse
adjustment knob
• Total magnification = (ocular lens power) x
(objective lens power)
• Example: (10x)ocular lens x (40x)high power
lens = 400x total magnification
• Magnification: The ability to increase the size
of an image
X
Ocular Lens
= 400x total
magnification
Objective Lens
Comparing Powers of Magnification
We can see better details with higher the
powers of magnification, but we cannot see
as much of the image.
Which of these images
would be viewed at a
higher power of
magnification?
Light Pathway: Light Source → Specimen →
Objective Lens → Body Tube → Eye Piece
Resolution- add this to your notes!
• making the image clear
• ability to determine between two objects or
points
• can be adjusted with the fine/course knob
or the diaphragm (to allow more light in)
Use of a Scope

Carry the microscope with 2 hands (arm & base)

Looking at a slide:
1. Use ONLY ONE slide at a time
2. ALWAYS start at LOW power first(10x)
3. ALWAYS start with stage lowered completely
4. Make sure the objective clicks into position
5. The coarse focus knob is ONLY used on the lowest
power lens
6. The fine focus knob is used on all lenses to bring
the image into focus
Putting the Microscope Away

Lower the stage completely and click the lowest
objective into place

Return slide to tray

Wind up the scope power cord
Types of Microscopes
1. Compound Light
2. Electron microscope:
Microscope: Shines
Uses electrons instead
light through a
of light to visualize the
specimen and uses 2
specimen, electrons
lenses for magnification bounce off or pass
through and a computer

Magnification – increase
interprets a picture
in an objects apparent
size


Resolution – how clear
the image appears once
magnified
Max clear magnification
~2000x
Always black and white,
specimen must be dead to
examine
Scanning EM – magnifies up
to 100,000x
Transmission EM – magnifies
up to 200,000x
Microscope Images
Compound Light Microscope - Protozoa
Scanning Electron Microscope (SEM
Butterfly Tongue
Transmission Electron Microscope - Bacteria