The document summarizes different types of microscopes. It discusses the invention of the light microscope in the 1600s and improvements that allowed higher magnification. Modern light microscopes use two lenses to magnify objects too small to see with the naked eye, typically at 100-1000x magnification. Electron microscopes were developed in the 1930s using electron beams instead of light, allowing magnification over 200,000x. Scanning electron microscopes bounce electrons off surfaces to create 3D images while transmission electron microscopes allow viewing internal structures by passing electrons through thin samples. Different microscopes are suited to different types of specimens.

1. Microscopy: The Science of the Microscope

2. The Invention of the Microscope
• Renaissance invention (Mid 1600s)
• Credit for invention goes to Anton Van Leeuenhoek
• Constructed simple curved glass lenses in combination

3. Improving the Microscope
• Robert Hooke
• English biologist who discovered cells
• Increased magnification with improved lenses

4. Modern Compound Light Microscopes
• Uses 2 lenses in combination to
magnify an image
• Can view objects too small to be seen
with unaided eye
• Object must be thin enough for light
to pass through
• Can view living things
• Typical magnification 100x to 1000x
See page 17 of your packet for a detailed discussion of:
• Parts and their functions
• Proper use and handling
• Procedures for making a wet mount

5. Pushing the Limits: Electron Microscopes
• A light microscope cannot be used to distinguish objects that are smaller than half
the wavelength of light
• Any object with a diameter smaller than 0.275 micrometers will be invisible or, at
best, show up as a blur
• Electrons are speeded up in a vacuum until their wavelength is extremely short,
only one hundred-thousandth that of white light.
• Electron microscopes were developed in the 1930s

6. Electron Microscopes
• Uses a beam of electron to view the specimen (not light)
• Specimen viewed must be prepared in a vacuum (no air molecules) therefore
living things cannot be viewed using this type of scope
• Magnifies up to 200,000x magnification

7. Scanning Electron Microscope

8. Scanning Electron Microscope or SEM
• Bounces electrons off the
surface of the object
• Produces a 3 dimensional
image of the object

9. Red Blood Cells

10. Blood Clot

11. Nerve Cells

12. Tongue with a Taste Bud

13. Sperm on Surface
of Human Egg

14. The Split
End of a
Human Hair

15. Tooth Plaque

16. Transmission Electron Microscope

17. Transmission Electron Microscope
• Electrons pass
through the object
forming a one
dimensional picture
• Allows one to view
the inside of an
object
(ex. internal
structure of a cell)

18. filamentous
bacteria from
the gut of a
termite

19. Sperm
heads
from a
stick
insect

20. Salmonella
Bacteria

21. Stereoscope
• Allows viewing of macroscopic objects with great detail
• Does not require light to pass through object
• Can view living things
• Typical magnification of 10X to 30X

22. Choosing the Correct Microscope

23. Microscope Lab Skills Review
Complete the microscope review activities on pages 41 and 43-44.