Name:
Matric No:
Class
Date:
LABORATORY INSTRUMENTATION & SAFETY
PRACTICAL 1: MICROSCOPY
Overview:
Microscope is an important device that enables us to visualize minute objects
(animate and inanimate) that cannot be seen by our naked eye. Major parts of
microscope:
A. Frame work of the microscope
- An arm (stand): - The basic frame of the microscope to which the base, body and
stage are attached.
- A stage: - the table of the microscope where the slide or specimen is placed.
- A foot, or base: - is the rectangular part up on which the whole instruments rest.
B. Focusing system
This encompasses:
-Coarse and fine focusing adjustments
C. Magnification system
• Objectives: - Objectives are components that magnify the image of the specimen to
form the primary image. For most routine laboratory work, 10x, 40x, and 100x (oil
immersion) objectives are adequate.
• Eyepiece
Objectives:
By the end of this experiment, you should be able to:
1. Know all the labeling part of light microscope
2. Observe bacterial slides by using light microscope
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PART 1: Label the parts of the light microscope : (10 MARKS)
1)
6)
2)
7)
3)
8)
4)
9)
5)
10)
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Materials:
Microscope, Bacterial Slides Specimen (Staphylococcus aureus / Escherichia coli /
Bacillus cereus/ Salmonella sp.), Immersion oil.
PART 2: Procedures for observe a bacterial specimen slides.
Each group will be provided with bacteria slides (Staphylococcus aureus /
Escherichia coli / Bacillus cereus/ Salmonella sp.) Observe at the slides under
microscope using procedures laid out below and draw the images of these bacteria
according to the respective magnification.
Always use this procedure when you observe a new microscope slide:
1.
2.
Turn the 4X objective lens into place.
Put the slide into the holder on the stage center the object to be seen over the
opening in the stage.
3. Use the coarse adjustment knob to move the stage as close to the lens as it will go
(a brake will prevent the slide from actually hitting the lens).
4. While looking,through the ocular, use the coarse adjustment knob to move the
stage away from the objective lens until the image is in focus.
5. Adjust the iris diaphragm for the proper amount of light.
6. To increase magnification, slowly turn the 10X objective lens into place.
7. Use the fine focus knob to bring it into proper focus.
8. Adjust the iris diaphragm for the proper amount of light.
9. To increase magnification further, slowly turn the 40X objective into place.
10. Use only the fine focus knob to focus.
11. For 100X objective, add a drop of immersion oil and rotate the 100X objective
lens into place.
12. Use coarse focus knob to raise the stage until the 100X lens just touches the oil.
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RESULTS
1. Draw the bacteria that you have observe under the light microscope:
Slide 1 (2 MARKS)
Name of bacteria: _________________________________________
Slide 2 (2 MARKS)
Name of bacteria: _________________________________________
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Slide 3 (2 MARKS)
Name of bacteria: _________________________________________
Slide 4 (2 MARKS)
Name of bacteria: _________________________________________
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Questions:
1) Explain why the 100X objective lens of the light microscope is immersed in
oil. (2 MARKS)
_____________________________________________________________________
_____________________________________________________________________
2) How you should carry a microscope? (2 MARKS)
_____________________________________________________________________
_____________________________________________________________________
3) List care and cleaning steps of microscope (4 MARKS)
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
_____________________________________________________________________
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