TOPIC: Microscope AIM: How do we use a microscope?

Eyepiece lens magnification x objective lens magnification Total magnification

Total magnification=4 x10= 40

100x 400x

Rules when using a microscope 1. Carrying microscope = 1 hand on arm, other hand under base close to body

2. DO NOT use coarse adjustment under high power bc it can break the lens or the slide

3. Always start off with low power bc it gives you a greater field of view. HIGH

4. Before switching to high power you must: a. focus your image b. center your image

5. Adjust the diaphragm (When switching from low to high, amount of light decreases)

6. Use LENS PAPER to clean lens

Treating specimen with solutions of different colors What is staining? Treating specimen with solutions of different colors Make cell parts more visible

Unstained cheek cells Stained cheek cells

Examples: 1. Lugol’s Iodine (plant cells)

Onion Cells stained with Lugol’s Iodine

2. Methylene blue (animal cells)

Cheek Cells Unstained Stained

Skin Cells stained with Methylene Blue

Wet mount 1. Place a drop of water on the slide

2. Place object on the slide.

3. Slowly lower cover slip onto specimen on an angle to avoid AIR BUBBLES.

4. Absorbed excess water with a paper towel.

F Upside down & backwards How do images appear? On the slide Seen through lens F

Image moves in opposite direction What happens when you move the slide?