1. DNA – November 17, 2010
What should this class sound and look like during a lab activity? (Describe what Ms. Moore would see if she came in here)
What happens if you do not follow the guidelines of the safety contract?

2. Introduction to Microscopes
Ms. Klinkhachorn
November 17, 2010
Biology

3. On Your Lab Handout…
Read the section titled “History and Importance of Microscopes”.
Answer the questions that follow.

4. How to Properly Carry a Microscope
You will be graded on this!
WALK slowly.
Hold the microscope at 2 points
One hand on the arm of the microscope
One hand underneath the base

5. How to Properly Carry a Microscope
Arm
Base

6. Identify Microscope Parts and What They Do
CAREFULLY go over the microscope and identify the parts.
You may move the parts GENTLY in order to figure out what the function of each part is.
Fill in the table below with this information.

7. Identify the Parts

8. Magnifies, Can Rotate to Increase/Decrease Magnification
Letter
Name
Function A
Objective Lens
Magnifies, Can Rotate to Increase/Decrease Magnification B
Stage Clips
Keep slide in place C
Diaphragm
Adjust the amount of light that goes through your object of study D
Light Source
Provides the light needed to see E
Ocular Lens / Eye Piece
Magnifies, Part that you look through

9. Supports the lenses, used to carry the microscope
Letter
Name
Function F
Arm
Supports the lenses, used to carry the microscope G
Stage
Holds the slide, moves up and down to help focus H
Course Adjustment Knob
Moves the stage up and down to focus the image (low power) I
Fine Adjustment Knob
Helps focus on higher powers J
Base
Supports the entire microscope, used to carry the microscope

10. Calculating Magnification
To calculate the total magnification using a compound light microscope, you must always multiply the power of the ocular lens by the power of the objective lens.
Total Magnification = Ocular Lens Power x Objective Lens Power

11. Sample Problem #1
Jared’s microscope has an ocular lens power of 20. He sets his objective lens power to 10. What will be the total magnification of the object he is observing?
Ocular lens = 20
Objective lens = 10
Total Magnification = 20 x 10 = 200

12. Sample Problem #2
Shelley’s ocular lens has a power of 50. She is looking at a cell under an objective lens of 20. What will be the total magnification of the object she is looking at?

13. Sample Problem #2
Shelley’s ocular lens has a power of 50. She is looking at a cell under an objective lens of 20. What will be the total magnification of the object she is looking at?
Ocular = 50, Objective = 20
Total Magnification = 50 x 20 = 1000

14. How to Store a Microscope
Remove any slides from the microscope
Move the objective lens to the lowest power.
Move the stage as far down as it can go.