1. Microscopes help us see small objects typically less than 500 nm
nm = nanometer = 1/1,000,000 mm
size of a human egg
size of a sharp pencil point

2. Magnification making an image appear larger than its actual size
not actually changing the size of the object

3. Magnification indicated by _____ X
i.e. an object that is 100X had been magnified 100 times
the bottom image is 1860X

4. Resolution the ability to distinguish the details of an image
measure of the clarity of an image

5. Resolution improved by adjusting the focus of a microscope
resolution capability of a microscope of may be determined by an object’s size and degree of detail

6. Resolution often displayed as a distance
a smaller distance means that a smaller object can be viewed clearly
a smaller distance means the microscope has better resolution

7. Magnification and Resolution
Both high magnification and good resolution are necessary to see small objects clearly.

8. Types of Microscopes
Compound Light Microscopes
Electron Microscopes

9. 1. Compound Light Microscopes (CLM)
more than 1
light
illuminating the object for clarity
light passes through two lenses to produce an enlarged image of a specimen

10. 1. Compound Light Microscopes (CLM)
magnification of an object observed using this microscope is the multiplication of the 2 (or more) lenses used to view the object
What is the possible compounded magnification of these lenses?

11. 1. Compound Light Microscopes (CLM)

12. 2. Electron Microscopes
microscopes shoot electrons at dead objects/specimens
as the electrons bounce back, the energy is recorded and translated into an image

13. 2. Electron Microscopes must be viewed in a vacuum vacuum
no air
no living cells can be viewed

14. 2. Electron Microscopes There are two types of Electron Microscopes
Transmission electron microscope (TEM)
Scanning electron microscope (SEM)

15. Transmission Electron Microscope (TEM)
Form 2D images
TEM images are always in black and white.
with the help of computers scientists add color to make things easier to see

16. Transmission Electron Microscope (TEM)
An electron beam is directed at a slice of a specimen that has been stained with metal ions.
Some structures become more heavily stained than others. Those heavily stained areas absorb electrons and in the lightly stained areas the electrons pass through hitting a fluorescent screen and forming an image on the screen.

17. Transmission Electron Microscope (TEM)

18. Scanning Electron Microscope (SEM)
essentially works the same as a TEM (electron beams)
shows 3D images of the surface of a specimen

19. Scanning Electron Microscope (SEM)
sample is coated with a very thin layer of metal
again, color has been added with a computer
Strain of Staphylococcus aureus bacteria (20,000x)

20. Scanning Electron Microscope (SEM)

21. Comparing Magnification and Resolution
Microscope Type
Magnification
Resolution
CLM
2,000 x
200 nm
TEM
50,000,000 x
50 pm
SEM
500,000 x
1 nm
(1 nm = 1,000 pm)
nm = nanometer (1 nm =1 billionth of a meter)
pm = picometer (1 pm = 1 trillionth of a meter)

22. Microscope Collage See Microscope Collage rubric.
Other Resources to use:
Textbook
Pages 50 – 54