1. Microscopes and Basic Measurement
How are they used to study the living environment?

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

3. 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

4. Practice Find Total Magnification: Ocular 2x, Objective 30x =
If Ocular is 10x and Total mag. = 350x
What is the strength of the objective lens?

5. Note:
As you increase magnification you need to let in more light to see your specimen (adjust diaphragm)

6. Resolution How sharp can you get the image?
Ability of microscope to distinguish two objects as being separate (ex: one cell from another)

7. What Happens to Image? Compound Microscopes:
Image becomes inverted and upside down

8. What Happens to Image? When you increase magnification
Object appears larger
Field of view gets smaller

9. 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)

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

11. Low power Magnification = High power FOV
High power Magnification Low power FOV
Ex: 100x = HP FOV
500x micrometers
500x =
HP FOV = 300 micrometers

12. Determining the Size of an Object Under a Microscope

13. View and draw object on low power
Estimate how many objects would fit across diameter of field of view

14. Divide the diameter of FOV by the number of objects that can fit across it.
Ex:
Three letter “e”s fit across FOV of 1800 micrometers
Each letter is about 600 micrometers
1800 micrometers = µm
3 letter “e”