Key Concepts
• The goal of microscopy is to create a magnified image of objects too small to be seen with the eye alone.
• Brightfield microscopes use a combination of glass lenses and light to view the specimen.
• Using an oil immersion objective lens allows for higher magnification.
• Microscopes are often used to study bacteria, cells, and tissues.
• Fields of study where a microscope is a necessary tool include:
o + Cytology
o + Histology
o + Microbiology
o – Pathology
Overview
• In this simulation, you will learn how to correctly switch from the 40X high powered objective lens to the 100X oil immersion lens.
• Oil immersion is an essential technique for light microscopy. Used only on the 100x power objective, oil immersion is when a drop of immersion oil is added to the slide, contacting both the sample and objective. Without this oil, some of the peripheral light that passes through the specimen is scattered into air or the slide, decreasing resolution.
Before you begin
• Immersion oil can only be used with the 100X objective lens. The oil must be properly removed before using the 4X, 10X, or 40X objectives lenses.
• Your instructor may have a different specific protocol for cleaning the microscope objective lens and the slide than presented in this simulation.
• Knowledge of how to operate a brightfield microscope is assumed in this lab simulation.
Methods
• Phase 1: Use of immersion oil
- Focus on the cell in the slide with the yellow star using 4X objective. Use coarse and fine focus knobs to focus image
- Rotate the nosepiece to 10x. Focus image using the fine focus knob
- Rotate the nosepiece to 40x. Focus image using the fine focus knob
- Rotate nosepiece halfway toward 100X objective (green ring). Apply one drop of immersion oil to slide
- Rotate 100X lens into oil drop. Use fine focus knob to focus image
- Rotate nosepiece to blank space next to 4x objective. Using lens paper, remove immersion oil from 100X objective and microscope slide
• Phase 2: Save Lab Data
Write your lab report in essay format. Your report must include the following in 1-2 pages:
• Introduction
• Hypothesis
• Methods
• Results
• Conclusion
• Resources cited
Sample Solution
