the mi croscope - plainviewcompound microscope (lesson objectives) •be able to identify the parts...

The Mi croscope

Learning about the microscope

Compound Microscope(lesson objectives)

• Be able to identify the parts and functions of the compound microscope.

• Be able to explain the procedures to making a wet mount slide.

• Be able to calculate total magnification.

• Be able to determine the size of an object (in micrometers) using a microscope

There are 2 kinds of

microscopes:

Simple: one lens (magnifying

glass)

COMPOUND MICROSCOPE

• Compound = 2 or more lenses

– Ocular Lens

– Objective Lens

.

Parts of the Microscope

1. Revolving

Nosepiece

Parts of the Microscope2. Lens/Objective

OBJECTIVE LENSES


3. Stage

Parts of the Microscope4. Diaphragm

(controls amount

of light)

DIAPHRAGM

1 = lowest setting

5 = highest setting


5. Light

source


6. Base


7. Eyepiece

EYEPIECE (Ocular)


8. Arm


9. Stage Clips

Parts of the Microscope10. Course

Focus/

Adjustment

COARSE ADJUSTMENT

FINE ADJUSTMENT


11. Fine

Focus/

Adjustment

12. Body

tube

Calculating Magnification

Multiply lens powers together!

• Eyepiece: 10 X by itself

• Scanning lens:

• 4X; red color

• Eyepiece X Scanning lens = total

• TOTAL magnification of 40 X

• mainly used for large objects/scanning


• Low Power: 10 X

• yellow color



• High Power: 40 X;

• blue color


• mainly used for smaller objects/details

When you are ready to start:

Make sure it is on SCANNING power!The stage should be all the

way down (you focus by slowly moving it up!)Check the light setting

(should be at 1-2 to start)

Other Things to Consider:

Carrying the Microscope: Always use 2 hands!

:Never use the

COARSE FOCUS KNOB while on HIGH power.

When putting the microscope away (at the end of the day):

It should be on SCANNING power.The stage should be all the way

DOWN (do this with the course focus knob!)

The light switch should be OFF

TROUBLESHOOTINGWhat if you can’t get your object into focus?

• Check that you have one of the lenses clicked into place

• Check that your disc diaphragm is in place (not IN BETWEEN settings)

TROUBLESHOOTINGWhat if you can’t get your object into focus?

• Clean off your lenses using LENS PAPER. (Also, dirty slides are hard to focus on; so clean them, too!)

• GO BACK TO LOW POWER AND START OVER!

There are 2 kinds:

• SCANNING ELECTRON MICROSCOPES (SEM)

• Allows you to see the SURFACES of objects

There are 2 kinds:

• TRANSMISSION ELECTRON MICROSCOPES (TEM):Allow you to see THROUGH an object.

Electron Microscope Images:

http://www.pbrc.hawaii.edu/bemf/microangela/

http://www.pbrc.hawaii.edu/bemf/microangela/

Using the Microscope!!

HOW TO USE

1. Set the microscope to the lowest power objective.

2. Lower the stage all the way using the ____________________.

3. Place the ____________ on the ________________.

4. Use the ________ adjustment to bring the stage all the way up.

5. Then focus on the object using the coarse adjustment.

6. Then use the ____________ adjustment to focus better.

7. Find what you are looking for and place it in the center of the field of

view.

8. Lower the ____________ by using the __________ adjustment.

9. Switch to the ___________ power objective.

10. Then focus, using only the _______________________.

coarse adjustment

slide stage

coarse

fine

stage coarse

high

fine adjustment

Microscope safety

1. Always use lowest power to scan the slide for the specimen.

Microscope safety

2. Never use coarse adjustment with high power objective!

why not??

because the stage will

cause the lens to crash

into the slide. This can

break the slide and/or

scratch the lens.

• 3. Use a microscope on

a solid, sturdy surface.

• Microscopes are made of

delicate and expensive parts.

Using a microscope on a

solid and sturdy will

minimize accidents and will

help you use a microscope

more easily..

© Stephanie Elkowitz42Microscopes

•

• 4. If a slide or coverslip breaks, do

not touch the broken glass.

• Be careful using glass slides and

coverslips. They are fragile. You must

handle them gently so they do not

break. If they do break, do not touch

the broken glass. Ask your teacher for

help cleaning up broken glass.

• ** Ask your teacher for help cleaning

up broken glass!

© Stephanie Elkowitz43Microscopes

Finding Total Magnification

Ocular Lens

XObjective Lens

LP= 150x

HP= 450x

Lets practice…

Remember the eyepiece is always ________ x !!!

What is the lowest possible magnification

that can be obtained using the

microscope shown?

1. 20x

2. 200x

3. 10x

4. 100x

© Stephanie Elkowitz49

• In order to view the specimen,

you must place it on the stage,

using the stage clips to hold the

slide in place.

• When viewing the specimen, the

lenses cause the specimen to

appear upside down and

backwards.

Microscopes


• If you view the letter “e” under the microscope (and it appears

normal on the stage), it would appear upside down and

backwards when viewed through the eyepiece.

How it appears on the slide

How it appears through the eyepiece

Microscopes


• When moving a specimen on the

stage, it will appear to move in the

opposite direction when viewing

through the eyepiece.

• If you move the specimen to the right

on the stage, it will appear to move to

the left through the eyepiece. If you

move the specimen down on the stage,

it will appear to move up through the

eyepiece.

Microscopes


• In order to center the specimen

(as viewed through the

eyepiece), you will have to

move the slide in the opposite

direction.

• For example, if the specimen

appears at the top of your

viewing field, you will have to

move the slide up on the stage

to center it.

Move the slide up...

Microscopes


• You must follow a specific series of

steps to focus a specimen with a

microscope.

• First, center the specimen on the

stage. Look through the eyepiece

using the scanning objective. Use

the coarse adjustment to bring the

specimen into focus. Center the

specimen in your viewing field by

moving the slide on the stage.

Microscopes


• Next, turn the nosepiece to

observe the specimen using the

low power objective.

• Use the coarse adjustment to

bring the specimen into focus.

• Use the fine adjustment to fine-

tune the focus. Center the

specimen in your viewing field by

moving the slide on the stage.

Microscopes

Field of view

• the area you see under the microscope for a

particular magnification

• Is the field of view larger or

smaller under high power?

100x 400x

FOV

• The lower the magnification, the Largerthe Field of view.

• The higher the magnification, the smallerthe field of view.

What do you notice about the amount of light when you switch from low power to

high power?

• There is less light.

• You need to adjust the diaphragm.

Field of View

• Under high power: The FOV is SMALLER and DARKER!

How to make a wet mount

• 1. Place specimen on a glass slide.

• 2. add a drop of water

• 3.Lower glass cover slip on an angle to avoid air bubbles.

• 4. examine under low power.

• Note: if stain is to be used, place drop of stain on one side of slide and pull it through using a paper towel.

How to Make a Wet Mount

To avoid air bubbles under

your slide, touch the

coverslip to the drop then lower it slowly, squeezing the

drop.

Microscope Lab

Examine the

functions and

magnification

of your

microscope.

Microscope Lab

A. Get to know the microsope.

B. Wet Mount of “d”.

C. Wet Mount of colored paper.

D. Look at 2 hairs.

E. 2 more slides.

p

The diagram represents a hydra as

viewed with a compound light

microscope. If the hydra moves to the

right of the slide preparation, which

diagram below best represents what will

be viewed through the microscope?

the mi croscope - plainviewcompound microscope (lesson objectives) •be able to identify the parts...

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