Transcript Microscope Notes ( use with pages 3 and 4 in the

You will be using a
compound light
microscope in class.
This type of microscope
has two lenses and a
light source that
illuminates the
specimen.
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# 1= Body Tube
• reflects light up to the viewer’s eye
Your eye goes here
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Body Tube
# 2= Nosepiece
• Can be rotated to change the objective
lens magnification
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# 3= Low-Power Objective Lens
• The 1st lens you use, 4x magnification
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# 4= Medium-Power Objective Lens
• The 2nd lens you use, 10x magnification
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# 5= High-Power Objective Lens
• The highest magnification lens,
40x magnification
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# 6= Stage Clips
• Keeps the slide in place
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# 7= Diaphragm
• Adjusts light, *usually better with low light
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# 8= Light Source
• Sends light up through the diaphragm and
through the slide for viewing
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# 9= Eyepiece/Ocular Lens
• The part you look in with your eye, 10x
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# 10= Neck/Arm
• Used to support the microscope when
carried.
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# 11= Stage
• Where the slide is placed
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# 12= Coarse Adjustment
• Makes large changes in focus, the bigger
knob, * NEVER use when viewing on
medium or high power!!
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# 13= Fine Adjustment
• Used to increase resolution/clarity, the
smaller knob
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# 14= Base
• Used to support the microscope when
carried
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The function of a microscope is to magnify
(enlarge the apparent size) a specimen. A
specimen is an organism or object being
magnified and observed. By magnifying a
specimen, biologists gain a more detailed
image of the object.
What’s my total power of magnification?
power of magnification = ocular lens magnification x objective lens magnification
Objective lens magnification
Ocular lens
magnification
What are the powers
of magnification for
each of
the objective lenses
on our microscopes?
Low- 4x
Medium- 10x
High- 40x
Different compound light microscopes may have different magnification powers!
Low
4X Objective
Medium
The specimen
appears
40 times larger.
The specimen
appears
100 times larger.
High
The specimen
appears
400 times larger.
Resolution
3. Clarity
4. Turn the fine adjustment knob to increase resolution
High Resolution
Low Resolution
Which of these images
were viewed at a higher
power of magnification?
4x
40x
5. What happens to magnification as you switch from the low
objective to the high power objective?
It increases
6. What happens to the field of view as you switch from the
low objective to the high power objective?
It decreases
Microscope Sketching
1.
2.
3.
4.
5.
All images must be drawn with a sharp pencil.
Must be detailed and neat. No color is added.
Labels are printed horizontally and neatly on the right side of the plate (circle
that shows the field of view). The labeling lines must be thin, neatly drawn with
a ruler, don’t cross, and end at the feature being identified.
Title is printed horizontally under the plate.
Total magnification is indicated at the lower right side of the plate.
Making a Wet Mount
Focusing a Specimen: A Step-by-Step Guide
1.
2.
Rotate the nosepiece to click the low-power objective (red stripe) in place.
Turn the coarse adjustment knob to raise the stage to its highest position.
3.
Place the prepared slide on the stage and secure it with the stage clips.
The specimen should be in line with the body tube and the stage opening.
4.
Use the coarse adjustment knob (large knob) to lower the stage and to
bring the image into view. Then use the fine adjustment knob (small
knob) to increase the resolution. Move the slide to center the image.
Adjust for light using the diaphragm.
5.
Once you have the image centered and in clear view, rotate the nosepiece
to the medium-power objective (yellow stripe). Do not use the coarse
adjustment knob here- only the fine adjustment knob should be used.
Center the image and adjust for light again.
6.
Repeat step 5 using the high-power objective (blue stripe).
Trouble Shooting
• First, make sure you turn on the microscope and the light
source is illuminated!!
• The slide should be secured with the stage clips.
• Always start on the low power objective.
• The objective lenses should click in place when rotating the
nosepiece.
• Be sure to make these three adjustments before moving on to
the next highest objective!
– Adjust the diaphragm to let in more light .
– Always center the specimen before switching objectives.
– Use the fine adjustment to increase resolution.
• Do not switch to the next objective if you did not focus the
image under the previous objective!
• Keep looking into the eyepiece when turning adjustment
knobs!
Let’s View the Letter “e” under
the microscope….
Low Power
Medium Power
High Power