1. Important Unit for Microscopes
Micrometers (microns) = µm
1/1000th of a millimeter
1000 micrometers = 1 mm

2. How Big is a Micron?

3. Early Microscopes Anton Van Leeuwenhoek (1670’s)
First to see and describe single celled organisms (protozoa)

5. Robert Hooke (1665)
Coined term “cell”

6. Earliest Microscope?

7. Parts of a Compound Microscope

8. Contain two lenses that cause light rays to bend in such a way to produce an enlarged image.

9. Lenses: Ocular Lens: eyepiece lens
Objective Lens: can be low, medium or high power
Look at magnification on lens
Lower power is smaller in size

10. Letting in Light:
Mirror or Illuminator: directs light up through the specimen
Diaphragm: regulates amount of light
Disk with different sized “iris” or openings

11. Arm: connects stage and body tube
Stage: platform with opening over which a specimen is placed (clips to hold slide)
Base: supports microscope

12. Eyepiece (ocular): part you look through, holds ocular lens, magnifies 10x
Body tube: connects eyepiece & objective lenses
Nosepiece: holds objective lenses (can be turned)
Objective Lens: magnifies image, can be low, medium, high power

13. Focusing: Coarse Adjustment Knob: use on low power only!!
(never use with high power
you can break your slide!)
Fine Adjustment Knob:
once low power is focused
switch to high power and use
fine adjustment.

14. Magnification How much can you enlarge the image?
Ex: 100x = 100 times as big

15. Finding Total Magnification
Multiply strengths of two lenses you are using.
Ocular lens x Objective lens
Ex:
Ocular = 10x
High Power Objective= 45x
Total Magnification = (10 x 45) = 450x

16. Finding Field of View (F.O.V)
Under Low Power: Use millimeter ruler
Ex: 1.5mm
Convert to micrometers
1 mm = 1000 micrometers
So 1.5 mm = 1,500 micrometers
(Move decimal over 3 to right)

17. Finding Field of View (F.O.V)
Under Medium or High Power
Need to set up a proportion
Remember!!
As magnification increases FOV decreases