Microscope: Parts, Function & History

• Understanding the parts and functions of a microscope is essential
• The goal is to identify microscope parts and focus specimens using a compound light microscope (CLM)

Short History of the Microscope

• The first microscope was built in 1595 by Hans and Zacharias Janssen in Holland
• In the 17th century it was perfected in several countries, including England by Robert Hooke, but most notably by Anton van Leeuwenhoek, a Dutchman
• The first compound microscopes made by the Janssens were a tube with lenses at each end
• These early microscopes magnified 3X to 9X, depending on the diaphragm openings

Developments in Microscope Technology

• Lenses were paired together to create compound microscopes and telescopes
• Pairing lenses increased magnification

Key Figures

• Robert Hooke (1635-1703) developed a primitive compound microscope
• In his book Micrographia (1665), Hooke coined the term "cell" to describe plant tissue, first discovering them under the microscope using cork from an oak tree
• Anton van Leeuwenhoek (1632-1723) was inspired by Hooke's Micrographia
• Leeuwenhoek used his new instrument, reaching 300x magnification with a single lens
• This was more powerful than Hooke's, enabling the discovery of microscopic things like protozoa and spermatozoa, and the microscopic structure of fleas and plant leaves
• Anton Van Leeuwenhoek was the first to see bacteria, yeast, and life in pond water
• He refined lens grinding to see living things through the microscope

Microscope Definition and Major Components

• A microscope is an optical instrument that uses lenses to produce magnified images of small objects
• A compound light microscope has three main categories: mechanical, magnifying, and illuminating

Microscope Parts and Functions

• Arm supports the tube and connects it to the base
• Base is the microscope's bottom, for support
• Eyepiece is where you look to see the specimen's image
• Body tube connects the eyepiece to the objective lenses
• Revolving Nosepiece is a part that holds multiple objective lenses that can be rotated to change power
• Stage is the platform where you place slides
• Fine Adjustment Knob is a small knob for fine-tuning specimen focus
• Coarse Adjustment Knob is a large knob for focusing
• Stage Clips hold the slide in place
• Iris Diaphragm controls light through the aperture
• Mirror/Light source is used to reflect light to the specimen
• Objective lenses increase magnification, with options like scanner, low, high, and oil immersion
• Aperture is the hole in the stage allowing light to reach the stage
• Condenser collects and focuses light from the illuminator onto the specimen, located under the stage with an iris diaphragm