Topic: Microscope

Aim: How do we use the compound microscope?

Do Now: Take out your homework.

Identify the microscope part being described as I walk around to check your homework (next slide).

HW: Ditto – Metric Conversions Part III #’s 4-10.

Let’s summarize…Identify the microscope part described.

1. Used to focus the specimen under high power.

2. Adjusts the amount of light reaching the specimen.

3. Platform slide is placed on.

4. Objective used to view a larger field of view needed to search for a specimen.

5. Used to focus specimen under low power.

6. Contains lenses.

7. Keeps slide in place.

8. Used to carry the microscope.

King Henry Died Before Drinking Chocolate Milk

King Henry Doesn’t Buy Dark Chocolate Milk

Total magnification:

Eyepiece x Objective

Power =

4x x10x

= 40x

100x

400x

4x 10x 10x 10x 10x40x40x 100x 400x

Low Power

High Power

How do images appear? e

Image on slide BEFORE placing it on the stage to view

How the image appears when viewing with the microscope

On the slide

Seen through lens

F

Whathappens

whenyoumovetheslide?

•Image moves in opposite direction

How must you always carry a microscope? •Always carry with 2 hands. One hand on arm and one hand under the base

Which objective must you always start with? Why? •Start off with low power bc of larger field of view.

LOW HIGH

Which adjustment is used when focusing the specimen under high power?

• Fine adjustment is used to focus under high power.

• DO NOT USE THE COARSE ADJUSTMENT UNDER HIGH POWER BECAUSE IT CAN BREAK THE OBJECTIVE LENS OR THE SLIDE!

What two procedures must be done BEFORE switching to high power?

- Focus your image - Center your image

What happens to the amount of light in your field of view when switching to high power?

LOW POWER MEDIUM POWER HIGH POWER

What happens to the amount of light in your field of view when switching to high power?

•The amount of light DECREASES.•Adjust the diaphragm to make it brighter.

What do you use to clean the microscope lenses?•Only use LENS PAPER for cleaning

Why do we stain cells?

Unstained cheek cells

Stained cheek cells

Cheek CellsUnstained Stained with Methylene

Blue

Skin Cells stained with Methylene Blue

Onion CellsUnstained Stained with Lugol’s

Iodine

Why do we stain cells?•To Make cell parts more visible

Wetmount

1. Place a drop of water on the slide

2. Place object on the slide.

3. Slowly lower the cover slip on an angle to prevent AIR BUBBLES.

4. Absorb excess water with a paper towel.

Let’s summarize…

1. Explain one rule that must be followed when using the microscope.

2. What do we use to make cell parts more visible?

3. Which way will a cell appear to move when moving the microscope to the left and down?

4. What happens to the image of the specimen when viewed with a microscope?

1. Will an object with a density of 3.4gm/cm3 sink or float in a cup of water? Explain why.

2. Will an object with a density of.086gm/cm3 sink or float in a cup of water? Explain why.