1. Microscopes Biology 11

2. The History 4 Many people experimented with making microscopes 4 Was the microscope originally made by accident? (Most people were creating telescopes) 4 The first microscope was 6 feet long!!! 4 The Greeks & Romans used “lenses” to magnify objects over 1000 years ago.

3. The History 4 Hans and Zacharias Janssen of Holland in the 1590’s created the “first” compound microscope 4 Anthony van Leeuwenhoek and Robert Hooke made improvements by working on the lenses Anthony van Leeuwenhoek 1632-1723 Robert Hooke 1635-1703 Hooke Microscope

4. The History Zacharias Jansen 1588-1631 The “First” Microscope

5. How a Microscope Works Convex Lenses are curved glass used to make microscopes (and glasses etc.) Convex lenses bend light and focus it in one spot.

6. How a Microscope Works Ocular Lens (Magnifies Image) Objective Lens (Gathers Light, Magnifies And Focuses Image Inside Body Tube) Body Tube (Image Focuses) Bending Light: The objective (bottom) convex lens magnifies and focuses (bends) the image inside the body tube and the ocular convex (top) lens of a microscope magnifies it (again).

7. The Parts of a Microscope:

8. Body Tube Nose Piece Objective Lenses Stage Clips Diaphragm Light Source Ocular Lens Arm Stage Coarse AdjCoarse Adj. Fine Adjustment Base

9. Body Tube 4 The body tube holds the objective lenses and the ocular lens at the proper distance Diagram

10. Nose Piece 4 The Nose Piece holds the objective lenses and can be turned to increase the magnification Diagram

11. Objective Lenses 4 The Objective Lenses increase magnification (usually from 10x to 40x) Diagram

12. Stage Clips 4 These 2 clips hold the slide/specimen in place on the stage. Diagram

13. Diaphragm 4 The Diaphragm controls the amount of light on the slide/specimen Turn to let more light in or to make dimmer. Diagram

14. Light Source 4 Projects light upwards through the diaphragm, the specimen and the lenses 4 Some have lights, others have mirrors where you must move the mirror to reflect light Diagram

15. Ocular Lens/Eyepiece 4 Magnifies the specimen image Diagram

16. Arm 4 Used to support the microscope when carried. Holds the body tube, nose piece and objective lenses Diagram

17. Stage 4 Supports the slide/specimen Diagram

18. Coarse Adjustment Knob 4 Moves the stage up and down (quickly) for focusing your image Diagram

19. Fine Adjustment Knob 4 This knob moves the stage SLIGHTLY to sharpen the image Diagram

20. Base 4 Supports the microscope Diagram

21. Caring for a Microscope 4 Clean only with a soft cloth/tissue 4 Make sure it’s on a flat surface 4 Don’t bang it 4 Carry it with 2 HANDS…one on the arm and the other on the base

22. Carry a Microscope Correctly

23. Using a Microscope 4 Start on the lowest magnification 4 Don’t use the coarse adjustment knob on high magnification…you’ll break the slide!!! 4 Place slide on stage and lock clips 4 Adjust light source (if it’s a mirror…don’t stand in front of it!) 4 Use fine adjustment to focus

24. Simple Microscope 4 Anton van Leewenhoek was the first to use the single lens microscope for biological purposes. 4 Consisted of 1 lens 4 used today for quick observations 4 specimens may be alive for examination.

25. Compound Light Microscope 4 Consists of two lenses 4 objective and eyepiece both of which magnify the image 4 these two lenses form the optical system. 4 Structural parts that hold the specimen and the lenses is called the mechanical system

26. Stereo microscope (dissection) 4 Contains an ocular and an objective for each eye 4 allows the scientist to view images as 3-D 4 used primarily for viewing external structures 4 specimens may be kept alive for examination.

27. Phase Contrast (lens) Microscope 4 Changes the way light passes through a living specimen so that you may see cellular parts not usually visible under a compound microscope. 4 Under the compound microscope the tissue would have to be dead, now it may be living. Frits (Frederik) Zernike won the Nobel prize 1953 for the development of this microscope.

28. Transmission Electron Microscope 4 Specimens are dead 4 an image can be magnified as large as 250, 000x. 4 Electron beam is sent through a vacuum chamber. 4 Electromagnets focus the image on a screen 4 denser materials appear darker than less dense material. Also know as the TEM

29. Scanning Electron Microscope 4 Like the TEM, this microscope uses electrons to focus an image and is able to view things much smaller than the light microscope. 4 Unlike the TEM, the SEM allows the viewing of 3D images. 4 However, the specimens are dead. Also known as the SEM

30. Magnification 4 The ability to increase the size of an image of a specimen. 4 The magnification of an image on a compound microscope is found by multiplying the power of the eye piece by the power of the objective. 4 The larger the magnification the less area you are able to see.

31. Resolution 4 The ability to show two points that are close together 4 in order for the increased magnification of a microscope to be of use, its resolution must also be increased 4 resolution is dependant on the quality of the lens.

32. Microscope Calculations: