The Microscope

The History

Zacharias Jansen1588-1631

The “First” Microscope

The History• Hans and Zacharias

Janssen of Holland in the 1590’s created the “first” compound microscope

• Anthony van Leeuwenhoek and Robert Hooke made improvements by working on the lenses

Anthony van Leeuwenhoek1632-1723

Robert Hooke 1635-1703

Hooke Microscope

How a Microscope Works

Convex Lenses arecurved glass used to make microscopes(and glasses etc.)

Convex Lenses bendlight and focus it inone spot.

The Parts of a Microscope

Body Tube

Nose Piece

ObjectiveLenses

High Power Stage Clips

Diaphragm

Light Source

Ocular Lens

Arm

Stage

Coarse Adj.

Fine Adjustment

Base

Skip to Magnification Section

Body Tube

Diagram

Nose Piece

• The Nose Piece holds the objective lenses and can be turned to increase the magnification

Diagram

A. Ocular Lens/Eyepiece

• Magnifies the specimen image

Diagram

B. Objective Lenses

• Increase magnification

Diagram

C. Stage and Stage Clips

• Supports the slide/specimen and holds the slide/specimen in place on the stage.

Diagram

D. Diaphragm

• Controls the amount of light on the slide/specimen

Turn to let more light in or tomake dimmer.

Diagram

E. Light Source

• Projects light upwards

Diagram

F. Base

• Supports the microscope

Diagram

G. Arm

• Used to support the microscope when carried.

Diagram

H. Coarse Adjustment Knob

• Moves the objectives up and down (quickly) for focusing your image

Diagram

I. Fine Adjustment Knob

• This knob moves the objectives SLIGHTLY to sharpen the image

Diagram

Magnification

Comparing Powers of Magnification

We can see better details with higher the powers of magnification, but we cannot see as much of the image.

Which of these images would be viewed at a

higher power of magnification?

A B

Magnification

• To determine your magnification…you just multiply the ocular lens by the objective lens

Objective Lenses have their magnificationwritten on them.

Ocular lenses usually magnifies by 10x

Magnification on OUR microscope

1. What is the magnification of OUR ocular lens?

2. What is the magnification of OUR low power objective lens?

3. Of our MEDIUM power?

4. Of our HIGH power?

10x

4x

10x

40x

Let’s Multiply the FUN!

• If you are looking at an object under LOW power, what is the total magnification of the microscope?

• Multiply the ocular lens (10x) by the objective lens (4x) to get total magnificiation.

• (10x) x (4x) = 40x

Caring for a Microscope

• Clean only with a soft cloth/tissue

• Make sure it’s on a flat surface

• Don’t bang it

• Carry it with 2 HANDS…one on the arm and the other on the base

Carry a Microscope Correctly

Using a Microscope• Start on the lowest magnification• Place slide on stage and lock clips• On LOW power, use the coarse adjustment to move

the stage up to its highest setting• Slowly move the stage down until you start to see

something.• Focus and center it BEFORE moving to a higher

power• Adjust light source (if it’s a mirror…don’t stand in front

of it!)• Don’t use the coarse adjustment knob on high

magnification…you’ll break the slide!!!– Use fine adjustment to focus

Clicker Time!!!

WOO HOO! I love

CLICKERS!!!

If you are looking at an object under low power, what adjustment should you use?

Fin

e H

igh

Low

Coar

se

4%

83%

9%4%

1. Fine

2. High

3. Low

4. Coarse

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If you are working on high power, what adjustment should you use?

9%

83%

4%

4% 1. High

2. Low

3. Fine

4. Coarse

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21 22 23 24

If you are working on Medium Power, what is your total magnification?

4%

65%

13%

17%

0% 1. 4x

2. 10x

3. 40x

4. 100x

5. 400x

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21 22 23 24

Which objective lens should you always start with?

9%

0%

91% 1. Low

2. Medium

3. High

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

21 22 23 24

How to make a wet-mount slide …

1 – Get a clean slide and coverslip from your teacher.

2 – Place ONE drop of water in the middle of the slide. Don’t use too much or the water will run off the edge and make a mess!

3 – Place the edge of the cover slip on one side of the water drop.

You do not need to use the stage clips when viewing wet-mount slides!

5 – Place the slide on the stage and view it first with the low power objective. Once you see the image, you can rotate the nosepiece to view the slide with the different objectives.

4 - Slowly lower the cover slip on top of the drop.

Cover Slip

Lower slowly

Using a Microscope• Start on the lowest magnification• Place slide on stage and lock clips• On LOW power, use the coarse adjustment to move

the stage up to its highest setting• Slowly move the stage down until you start to see

something.• Focus and center it BEFORE moving to a higher

power• Adjust light source (if it’s a mirror…don’t stand in front

of it!)• Don’t use the coarse adjustment knob on high

magnification…you’ll break the slide!!!– Use fine adjustment to focus