1. Microscopy Honors Biology 2006-2007

2. Orders of Magnitude What would it look like to go from 10 million light years from Earth to an atom in an oak tree leaf in Tallahassee, Florida? Let’s see….shall we? Honors Biology 2006-2007

4. Vocabulary Honors Biology 2006-2007 1.Magnification - making an image appear larger than its actual size. 2.Resolution - how clear an image is 3.Microscope - instrument for viewing objects too small to be seen by the naked eye. 4.Field of View - how much area you actually see when looking through the microscope 5.Depth of Field - the thickness of the specimen that is acceptably sharp at a given focus level

5. Microscope History Honors Biology 2006-2007 Zaccharias Janssen and son, Hans (1590): Lenses Galileo (1609): Magnifying tube Robert Hooke (1665): Compound microscope & cork Anton van Leeuwenhoek (1674): microscope powerful enough to see bacteria

6. How do we “see”? Honors Biology 2006-2007 Kinds of Microscopes 1.Dissecting Microscope 2. Optical (Light) Microscopes 3.Scanning Electron Microscope 4.Transmission Electron Microscope

7. Dissecting Scope  Light illuminated  Image is 3-D  Low magnification  Used primarily during dissection for better views of specimen.  Cannot view individual cells. Honors Biology 2006-2007

8. Light (Optical) Microscopes  Light passes through specimen  Refractive lenses  COMPOUND light microscopes use 2 lenses  2-Dimensional  ~ size of a bacterium  Usually magnifies 10x or 40x, 100x, and 400x  But up to 1500x  Can be used to study live cells Honors Biology 2006-2007

9. Electron Microscopes  Uses electrons to form an image of an object  100x light microscope  i.e. viruses and bacteria  Magnification: up to 200,000 x  Can only be used on dead cells Honors Biology 2006-2007

10. 2 Kinds of Electron Microscopes 1)Transmission Electron Microscope (TEM) Electron beam through thin section of specimen 2D image 2)Scanning Electron Microscope (SEM) Specimen - whole & plated in gold Electrons ‘bounce off’ sample 3D Image Honors Biology 2006-2007

11. What in the World? Honors Biology 2006-2007

12. What in the World? Honors Biology 2006-2007

13. What in the World? Honors Biology 2006-2007

14. What in the World? Honors Biology 2006-2007

15. What in the World? Honors Biology 2006-2007

16. SEM Images Honors Biology 2006-2007

17. SEM Images Honors Biology 2006-2007

18. The Compound Light Microscope  Eyepiece  Lower-power objective  Nosepiece  Body tube  Coarse adjustment  Fine adjustment  Stage  Stage clips  Diaphragm  Light source  Arm  Base Honors Biology 2006-2007

19. Using a Compound Light Microscope 1) Total magnification = Eye piece x objective lens  Example: (10x) x (30x) = 300x Magnification Examples 2)Cover slips - No bubbles! 2)Focusing - Coarse 1st! Honors Biology 2006-2007

20. Making a Wet Mount Slide Honors Biology 2006-2007

21. Questions  How do you place a cover slip on a slide?  What objective do you start your viewing with?  As you focus, what do you need to be sure to watch out for? Honors Biology 2006-2007