Microscopes - kphelanxhs

Microscopes
How are Microscopes Used?
• Micro “tiny” – scope “to view”
• How big is a…..
• Can see substances or structures not
visible to the naked eye
• Magnify very small objects (not just living
things!)
• Identify and Compare species
• Measure size and compare
Word Bank
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Eyepiece
Course Adjustment Knob
Diaphragm
Stage
Arm Support
Stage Clips
On your Microscope, Label
Base
the Parts of the Compound
Light Microscope
Light Support
Nosepiece
Fine Adjustment Knob
Objective Lenses
Microscope Terms
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Definition: clarity; how clear the specimen appears
Magnification: amount of enlargement of an image
Orientation: way in which something appears to be directed
Depth of Field: refers to layers, 3-D effect that is viewable
by changing fine adjustment under high power
• Width of Field: distance across the diameter of your field of
view, used to estimate the size of a specimen
• Micrometer: metric unit of measure
– 1millimeter = 1,000 micrometers
• Objective: degree of magnification
Low =
Med =
High =
Steps to Storing a Microscope
1.) Turn off light and allow to sit for 5 min to cool
down.
2.) Turn the stage all the way down.
3.) Return objective to low.
4.) Remove slide. Rest the stage clips on the
stage.
5.) Loosely wrap and secure the electrical cord.
6.) Turn the ocular over the body tube.
7.) Cover the microscope with the jacket.
8.) Carry the microscope with two hands.
9.) Place the microscope in the closet with the
ocular pointing out.
Steps to Focusing a Microscope
(Know in Order!!)
1.) Turn light on and leave it on for as long as you are using the microscope.
2.) Align the slide on the stage and secure with the stage clips.
3.) Turn the ocular towards you by rotating the base, not the tube.
4.) Using the coarse adjustment, bring your specimen into view, and center it in
your field.
5.) Adjust the diaphragm for the “best” lighting, not necessarily the brightest
setting.
6.) Using your fine adjustment, sharpen your image (give the image definition.)
7.) Using the revolving nose piece, turn to your medium power objective.
8.) Using the coarse adjustment, bring your best image into view, center it, and
turn the fine adjustment for definition.
9.) Turn the high power objective into place using the nosepiece. Using only
the fine adjustment knob, fine tune your image.
10.) You may also want to change the light for a better image at this point.
What type of Microscope do I
need to see…..
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Chloroplast (organelle)
Cancer Cells
Water Flea
Virus
Muscle Tissue
Snowflakes
What type of Microscope do I
need to see…..
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Chloroplast (organelle)
– SEM
Cancer Cells
– Compound Light
• OR SEM
(depends on purpose)
Water Flea
– Compound Light
Virus
– TEM
(color artificial)
Muscle Tissue
– Compound Light
Snowflakes
– SEM
Measuring Using the
Microscope
We cannot just measure a
specimen using a ruler, so
we need to indirectly
measure or compare the
size to something we
already know!
Width of Field or
Width of View
WFLP = Width of
Field Low Power
WFHP = Width of
Field High Power
REMEMBER=
Micrometer μm
Measure the WFLP
Place the ruler on the stage so that it
covers half of the stage opening and
you can see markings
1. Make sure the ruler is
centered at the center of the WF
2. What is the field of view in
scanning power to the nearest in
millimeters?
GOOD 
3. Switch to medium power and
calculate the magnification.
4. You cannot measure the field
for high-power, so you need to
estimate……
Mag LP = WFHP
Mag HP WFLP
Before measuring a specimen, you
need a table like this….
TOTAL Mag
Low
Medium
High
Estimated WF
(using ruler)
Calculated WF
Let’s try it #1…
Ocular power = 10x
Low power objective = 20x
High power objective = 50x
Mag LP = WFHP
Mag HP WFLP
a. What is the highest magnification you could get
using this microscope?
b. If the diameter of the low power field is 2 mm,
what is the diameter of the high power field in
μm?
c. If 10 cells can fit end to end in the low power
field of view, how many of those cells would you
see under high power?
Let’s try it #2…
Ocular power = 10x
Low power objective = 10x
High power objective = 40x
a. What is the approximate width of the field of view in
micrometers?
b. What would be the width of the field of view under
high power?
c. If 5 cells fit across the high power
field of view, what is the appropriate
size of each cell?
Let’s try it #3…
Ocular power = 10x
Low power objective = 20x
High power objective = 40x
a. If viewed under low power, what is the
approximate size of the cell in micrometers?
b. What would be the high power field of view?
c. How many cells like the
CELL
one in the picture could
fit in the high power
field of view?
2000 μm
Drawing in the Lab Notebook
Drawing # : Title
WF(under total mag)
# of specimen in field
cell
Observations:
Date:
Total mag:
Sig:
Each drawing should
consume ½ a page in
your notebook!
Making a Wet Mount
• Carefully angle the cover-slip and slowly
place on the specimen.
• Water should NOT ooze out of the coverslip
• Do not drop the cover-slip on the
specimen- avoid bubbles
Whiteboard Discussion
• For the lowercase “a” drawing, what observations were you
expected to make?
• In completing the paramecium drawing, what did you find
about comparing the actual size of the specimen when you
moved from low to high power? Did the image change? Did
the specimen’s numerical width change?
• After creating the starfish development picture, were you able
to relate the egg’s size to that of a different specimen in a
different power (i.e. the paramecium in high power)?
• When you observed the last slide, how did you decide what
power to draw that specimen under?
What is on the test???
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Microscope parts and functions
How to properly store a scope
How to focus an image (steps in order)
How to draw a specimen
Which microscope should I use?
Microscopic Calculations
How to work and use the scope (what objective
to use, how to draw, basically the lab)
It is all about perspective!
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