3.2: Light Microscopy Procedure
Light Microscopy Procedure
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The following activity will teach students how to use a compound light microscope and oil immersion lens. Read the following procedure carefully before starting the activity
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Step 1: Get into groups of 2 and decide which five slides you will work with. Make sure you select one slide of each type specified in the materials column. Collect the remaining materials listed.
Step 2: Microscopes should be set with the stage down and on the lowest dry objective, 4x, before you begin. Make sure your microscope is plugged in and the light turned on.
Step 3: Place one slide on the microscope stage in between the stage clips. Use the course knob to move the slide up towards the 4x dry objective until the specimen is focused.
Step 4: Switch to the 10x dry objective and use the fine knob to re-focus the image.
Step 5: Switch to the 40x dry objective and use the fine knob to re-focus the image.
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Step 6: When the specimen is focused on the 40x objective. Slightly move the nose piece so that the 40x dry objective and 100x oil immersion objective straddle the slide. At this point, an objective lens should not be near or touching the slide, they should be located on each of the slide.
Step 7: Add a small amount of immersion oil onto your slide then gently move the 100x oil immersion objective onto your specimen. You may need to use the fine knob to fix focus slightly. Record your observations below.
Step 8: When you are done viewing your specimen, you must clean your microscope. First, spray lens cleaner onto lens paper. NEVER spray cleaner directly on the microscope, this will damage it.
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Observation Results
Observe your five microscope slides under oil immersion. Write the name of the specimen you selected, illustrate the magnified image, and record your total magnification.
Observation Results
Observe your 5 microscope slides under oil immersion. Write the name of the specimen you selected, illustrate the magnified image, and record your total magnification.
Label The Parts of the Microscope
Figure 1. Label the 9 parts of the microscope.
General Questions
1. Do all microbes have the same structure? Explain your reasoning.
2. What is the purpose of using immersion oil?
3. What is the function of the:
A) Ocular Lens:
B) Coarse and Fine Knob:
C) Nosepiece:
D) Diaphragm:
4. How can resolution and contrast be increased?
5. A microscope has 10x power ocular lens and a 60x objective lens. What is the total magnification power of this microscope?
Health-Related Questions
1. What microbial agent causes malaria?
2. What are the advantages of using a microscope to determine if a patient has malaria?
3. How do we use a microscope to determine if the Plasmodium parasite is present in a blood sample?
Attributions
"Microbiology Laboratory Manual: Labs, 1.4 Microscopy" by Dr. Rosanna Hartline , LibreTexts: Biology , West Hills College Lemoore is licensed under CC BY-NC-SA 4.0
"Microbiology Laboratory Manual: Labs, 1.5 Get to Know the Microscope and Microbes" by Dr. Rosanna Hartline , LibreTexts: Biology , West Hills College Lemoore is licensed under CC BY-NC-SA 4.0
Image Citations
Figure 1. " Part of a microscope " by Sue Waters on Creative Commons is licensed under CC BY-SA 2.0