1. Microscopes

2.  Invented by Robert Hooke and Antoni van Leeuwenhoek  One of the most widely used tools in Biology  An instrument that produces an enlarged image of an object

3. Magnification & Resolution  Magnification- increase in an object’s apparent size  Resolution- the power of a microscope to clearly show detail

4. Types of Microscopes  Compound Light Microscope (LM)  Electron Microscopes Transmission Electron Microscope Scanning Electron Microscope (SEM)

5. Compound Light Microscope  LM  Thin sliced (enough to be transparent) & sometimes stained specimen is mounted on a glass slide to be viewed  The slide is placed on the stage and a light source (a light bulb in the base) directs the light upward

6. Compound Light Microscope  Light passes through the specimen and through the objectives lens, which is positioned directly above the specimen

7. Objective Lenses  A set of objective lenses is located on the rotating nosepiece enlarges the image of the specimen with different powers of magnification.  The most powerful objective lens produces an image 40 times (40X) the actual size of the specimen

8. Compound Light Microscope  From the objective lens, the magnified image is projected up through the body tube to the ocular lens in the eyepiece where it is magnified further (10X)

9. Total Magnification  Multiply the power of magnification of the lens being used (40X, 100X) by the power of magnification of the ocular or eyepiece lends (10X)  Example: 40 x 10 = 400x total power of magnification

10. Resolution Power  The resolution power of LM’s is limited by the physical characteristics of light  At powers of magnification beyond 2000x, the image of the specimen becomes blurry

11. Parts of a Compound Light Microscope  Ocular Lens  Body Tube  Revolving Nosepiece  Objectives  Stage Clips  Diaphragm  Light Source  Arm  Stage  Coarse Adjustment Knob  Fine Adjustment Knob  Base

12. Compound Microscope  Lab