1. The Microscope Lab. Manual No.1 Dr. Mohammed Hussein
M.B.Ch.B – MSc – DCH (UK) –MRCPCH

2. Microscope
Light Microscope
Electron Microscope

3. Light Microscope
Invited by a spectacle maker, Zacharias Janssen, around the year 1590

4. Light Microscope (LM)
The light microscope (also called an optical or compound microscope ) uses lenses and light to enlarge the image

6. Coarse & Fine adjustment knobs
Eyepiece
(Ocular lenses)
Head
Revolving nosepiece
(Turret)
Arm
Objective lenses
Stage
Coarse & Fine adjustment knobs
Condenser
Stage motion knob
Power switch
&
Brightness control
Base
Illuminator (Lamp)

7. LENSES
The light microscope has two systems of lenses for greater magnification:
1) The ocular, or eyepiece lens that one looks into
2) The objective lens, or the lens closest to the object

8. X 10
Ocular Lenses
Objective Lenses
X 1000
X 400
X 100
X 40

9. Light Microscope (LM)
The Magnification power of the LM is limited to X.
The Resolving power (resolution) of the LM is 0.2 µm.
The resolving power (resolution) is defined as the smallest distance between two particles at which they can be seen as separated objects.
Note: 1 µm = 1e-6 m

10. How to Focus Your Microscope

11. Start with the lowest power objective lens first and while looking from the side, crank the lens down as close to the specimen as possible without touching it.
Now, look through the eyepiece lens and focus upward only until the image is sharp. If you can’t get it in focus, repeat the process again.
Once the image is sharp with the low power lens, you should be able to simply click in the next power lens and do minor adjustments with the fine adjustment knob.
Continue with subsequent objective lenses and fine focus each time.

12. Notes
Both eyes should be open when viewing through the microscope. This prevents eye fatigue, which occurs when the non-viewing eye is kept closed. Keeping both eyes open does take some practice, but it is highly recommended.
Also, you should never let your eye touch the ocular lens. If your eyelashes touch the lens you are to close.
Always remove eyeglasses when viewing through a microscope. If your eyeglass lens touches the microscope it may get scratched.

13. Electron Microscope (EM)
The Magnification power of the EM is limited to 2,000,000 X.
The Resolving power (resolution) of the LM is 0.1 nm.
Note: 1 nm = 1e-9 m

14. Types: Transmission Electron Microscope (TEM)
Scanning Electron Microscope (SEM)

15. Transmission Electron Microscope (TEM)

16. Scanning Electron Microscope (TEM)