1. Microscopes Developments of microscopes have been dependent upon :
Development of glass
Glass into lenses
Variety of lenses and eventual assembly into the microscope
Beyond microscopes – viewing developments
Stains
Sectioning
Different kinds of light 6

2. Microscopes
Microscopes are used for viewing cells and other small objects too small to be seen with the naked eye. They magnify the image, while retaining resolution (fine detail).

3. Microscopes Light microscopes (USE LIGHT) Simple light microscope
Compound light microscope
Phase-contrast microscope
Fluorescence microscope
Scanning confocal microscope
PlasDIC microscope
Electron microscopes (USE ELECTRONS)
Transmission electron microscope
Scanning electron microscope
Electrons: 7

4. A MICROSCOPE HAS TWO FUNCTIONS To resolve and magnify
Resolution- Clarity of an image. Being able to see the fine details of an image. SHARP lines not blurry lines.
Magnification- enlarge an image. Make it bigger.

5. Light Microscopes Vs Electron Microscopes
Light Microscope: A type of
microscope which uses visible light
and a system of lenses to magnify
images of small samples.
Electron Microscope: A microscope
that uses a beam of electrons to form an
image on a photographic plate of a screen.
Because high energy electrons can have a much shorter wavelength (about 0.004nm) than visible light (green light has a wavelength of 550nm) an electron microscope can have a resolution of about 2nm, about 100 times better than light microscopes.

6. Light Microscopes
Increase ability of human eye to see tiny objects (cells; organelles)
Use visible light that illuminates and passes through specimen
Slice of tissue is examined (a few cells thick)
Tissue is usually stained to increase visibility
Simple Light Microscope
Use glass lenses
Similar to a magnifying glass
Compound Light Microscope
At least two sets of objective lenses of different magnification (changes how large object appears)

7. Compound Light Microscope10

8. Resolution and Staining
The ability to see two points (close together) as two separate points
Human eye has limited resolving power (see the two points together as a blur)
Staining
Cells are virtually colourless and difficult to see
Cut into thin slices and stained 11

9. Electron Microscopes Transmission Electron Microscope (1930s)
Beam of electrons (instead of light) of shorter wavelength, passes through specimen to illuminate
A series of electromagnets (instead of lenses) are used to control electron beam
Greater resolving power than light microscopes
Scanning Electron Microscope (1965)
Used to provide detailed image of surfaces
Uses beam of electrons scanned along surface of specimen to form an image on a fluorescent screen
Can only view dead cells or organisms

10. Transmission Electron Microscope12

11. Scanning Electron Microscope Images

12. An ant, Formica fusca, holding a microchip

13. Surface of an Erasable Programmable Read-Only Memory silicon microchip

14. The surface of a strawberry

15. Bacteria on the surface of a human tongue

16. Human sperm (spermatozoa)

17. Nylon hooks and loops of Velcro

18. Household dust: includes long hairs  of cat fur, twisted synthetic and woolen  fibers,  serrated  insect scales, a pollen grain, and plant and  insect remains

19. The weave of nylon stocking fibers

20. Head lice clinging to a human hair

21. The head of a  mosquito

22. Eight eyes (two groups of four) on the head of a tarantula

23. Cut human hairs and shaving foam between two razor blades

24. Paper from a Cigarette

25. Corroded surface of a rusty nail

26. Mushrooms spores
SPORE: a minute, typically one-celled, reproductive unit capable of giving rise to a new individual without sexual fusion, characteristic of lower plants, fungi, and protozoans.

27. Clutch of butterfly eggs on a raspberry plant

28. Calcium phosphate crystal

29. Microscopes: FACT FILES