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Overview of Microscope Components

Sep 30, 2025

Overview

This presentation explains the main parts of a compound light microscope and describes the function of each component.

Main Parts of the Microscope

  • Eyepiece Lens (Ocular Lens): The first point of magnification, usually 10x or 15x. This is the lens you look through.
  • Barrel (Body Tube): Connects the eyepiece lens to the objective lenses.
  • Arm: Supports the microscope, raising the objective lenses above the stage. Also used for carrying the microscope.
  • Objective Lenses: The second point of magnification. Mounted on a revolving nosepiece and color-coded: 4x (red), 10x (yellow), 40x (blue), and 100x oil immersion (gray).
  • Stage: The platform where the slide is placed for viewing. The slide is held by slide clips and the stage can be moved in four directions using stage controls.
  • Coarse and Fine Focus Knobs: Move the stage toward or away from the objective lenses. The coarse focus brings the specimen into focus, while the fine focus sharpens the detail.
  • Lamp: The light source for the microscope, with adjustable brightness.
  • Diaphragm: A rotating disc under the stage that controls the intensity of light passing through the slide.
  • Base: The bottom support of the microscope. The base should be held along with the arm when carrying the microscope.

Key Terms and Definitions

  • Eyepiece Lens (Ocular Lens): The lens at the top of the microscope for initial magnification.
  • Barrel (Body Tube): Connects the eyepiece to the objective lenses.
  • Arm: The supporting structure for the body tube and lenses; also used for carrying.
  • Objective Lenses: Multiple lenses with different magnifications, mounted on a rotating nosepiece and color-coded.
  • Stage: The platform for placing slides, with clips to hold the slide in place.
  • Stage Controls: Allow movement of the stage and slide in four directions.
  • Coarse Focus Knob: Moves the stage for general focusing.
  • Fine Focus Knob: Fine-tunes the focus for detail.
  • Lamp: Provides light for viewing the specimen.
  • Diaphragm: Adjusts the amount of light passing through the slide.
  • Base: The bottom part that provides stability and support.

Actions / Next Steps

  • Study and memorize the names, locations, and functions of each microscope part.
  • Practice identifying each part on a real or diagrammatic microscope.
  • Review proper handling and carrying of the microscope using the arm and base.
  • Familiarize yourself with focusing and adjusting light for optimal viewing.