Practical Biology Biol 101

Lab 2

MICROSCOPE & APPLICATIONS

Hail UniversityFaculty of Sciences

Department of Biology

Microscope Lab Objectives

Identify the parts of dissecting and compound light

microscope and give their functions.

Coordinate their use to accurately focus on materials

provided at the levels of magnification indicated on your

response sheet without damaging the microscope or slides.

Demonstrate proper procedures for cleaning and preparing

microscopes for use and returning them to their assigned

storage place in proper condition.

Common Microscope Types

Dissecting Compound

Binocular

Electron

microscope

Dissecting microscope : Allows one to study the entire object in three dimensions. (Examples: insects and leaves)

The compound light microscope :Uses light rays which are magnified and focused by means of lenses. This type is used to examine tiny or thinly sliced cross sections.

Electron microscopes : Uses a beam of electrons which are magnified on a photographic plate by means of an electromagnetic lens.

Microscope Type Uses

Compound Light Microscope Parts & Functions

Eyepiece: Magnifies material

being viewed by 10X The part of the

microscope you look into

Sometimes contains a pointer that can be seen as you look into the eyepiece.

May also be called the ocular.

Microscope Parts & Functions

Nose piece:

Part of microscope to which the objectives are attached

Rotates to allow for the changing of objectives to increase or decrease magnification.

Microscope Parts & Functions

Arm: Part of microscope to

which the nosepiece is attached

A secure part of the microscope to hold on to when the microscope is being carried.

Sometimes includes a cord hanger for power cord storage

Microscope Parts & FunctionsObjectives: Magnify material

being examined Scanning

magnifies 4X 10X

magnifies 10X High dry

magnifies 40X Oil immersion

magnifies 100X

Total magnification = magnifying power of eyepiece x The magnifying power of the objective in use.

Microscope Parts & FunctionsStage: Platform on which

microscope slide rests

Mechanical Stage: Used for adjusting the

position of the slide for viewing

Slide holder: Secures slide to the

mechanical stage

Mechanical Stage control knobs:

Move the slide

Microscope Parts & Functions

Coarse adjustment knob: Coarse focusing

Fine adjustment knob: Precise focusing

Microscope Parts & Functions

Substage condenser concentrates light & directs it

through opening in microscope

stage

Iris diaphragm: regulates the amount of light

passing through the substage

condenser

increases resolving power of the

microscope

Microscope Parts & Functions

Iris diaphragm lever:

adjusts the iris diaphragm to increase or decrease microscope resolutionCondenser control

knob: raises & lowers

condenser

Microscope Parts & Functions

Illuminator Light source

Illuminator control: Controls the intensity of

light Serves as the on/off

switch for some microscopes

Base:o provides support for

microscope

Microscope Storage

Microscope Cabinet Individual Storage

Microscope Storage

Always with a dust cover

Microscope Transport

Always with one hand on the arm & one on the base.

Preparation for Storage

Clean microscope

Rotate shortest objective (4X) into place over stage

Lower stage for max distance between objective & stage

Wrap cord around base or on cord hanger

Preparation for Storage

Adjust mechanical stage so nothing sticks out from the sides

Replace dust cover

Return microscope to storage area

Preparation for Use

Transport microscope to work station

Remove dust cover

Plug in microscope

Inspect and clean microscope

Microscope Cleaning

Use only lens paper to clean glass parts of microscope.

Use glass cleaner with lens paper to remove immersion oil from objectives, etc.

Kimwipes or paper towels may only be used to clean microscope slides & non-glass parts of the microscope.

1. O b t a i n l e t t e r e a n d p l a c e i t o n a c l e a n d r y s l i d e .

2. A d d a d r o p o f w a t e r a n d c o v e r w i t h a c o v e r s l i p b y h o l d i n g

t h e c o v e r s l i p a t a 4 5 o a n g l e t o t h e d r o p o f w a t e r w i t h o n e

e d g e o f t h e c o v e r s l i p o n t h e s l i d e . T h e n g e n t l y a n d s l o w l y

l o w e r t h e c o v e r s l i p o v e r t h e d r o p t o g e t r i d o f a i r b u b b l e s .

3. P l a c e y o u r s l i d e o n t h e s t a g e , a n d h o l d t h e s l i d e i n p l a c e b y t h e c l i p s . B e s u r e t o h a v e t h e s t r u c t u r e t o b e e x a m i n e d o v e r t h e o p e n i n g o f t h e s t a g e .

Prepare a wet mount using letter "e" from a newspaper.

4. O b s e r v e u n d e r t h e o c u l a r a n d f o c u s u s i n g t h e c o a r s e

a d j u s t m e n t k n o b u n t i l h e i m a g e " e " i s c l e a r. A l w a y s b e g i n y o u r

e x a m i n a t i o n w i t h t h e l o w e s t p o w e r o b j e c t i v e l e n s ( 4 X ) . M a k e

s u r e t h a t t h e l e n s d o e s n o t t o u c h t h e s l i d e .

5. O n c e t h e s t r u c t u r e i s s e e n i t m a y b e n e c e s s a r y t o a d j u s t t h e

a m o u n t o f l i g h t b y r o t a t i n g t h e d i a p h r a g m s l i g h t l y s o t h a t y o u

g e t m a x i m u m i l l u m i n a t i o n . A l s o , a d j u s t t h e c o n d e n s e r.

6. U s e t h e fi n e a d j u s t m e n t k n o b t o s h a r p e n t h e f o c u s i f n e e d e d .

7. W h e n l o o k i n g t h r o u g h t h e e y e p i e c e , p r a c t i c e h a v i n g b o t h

e y e s o p e n .

Prepare a wet mount using letter "e" from a newspaper.

Unicellular organisms

Paramecium

Multicellular organisms

Human Epithelial Cells (400X)

THANK YOU