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The Microscope

Laboratory   No. – 1-

Microscope

       One of the most important instrument that will use in biology laboratory .

       The "micro " word means small , the second word " scope " means something for looking with .

Type of microscope :

A- light ( compound ) microscope .

B –dissecting microscope .

C- flu recent microscope .

D- electronic microscope .

The compound microscope

       Uses tow sets of lenses , Ocular and objective . there are tow types of compound microscope according to number of ocular lenses :

  1- monocular microscope (one ocular lens)

  2- binocular microscope ( tow ocular lens ).

Part of compound microscope :

The microscope included four system :

A- Supporting system

      1- Base : the bottom portion on which the microscope rests .

      2- Arm : curved part in which the microscope its carried .

      3- Stage : a palate form on which slides to be studies are                             placed , the opening in the center allows light to                          passé from below through the object being                                   examined .

   4- mechanical stage: an adjustor knob below the stage move                                        the stage forward and backward and                                            from side to side .

    5- Stage clip : tow clips mounted on the stage that hold slides                               in place .

  6- Body tube : the portion that receive the ocular .

B- Illumination system

 1- Light : come from a lamp that  fix into the base of the                               microscope .

2- Condenser : A lens located beneath the stage opining that                               controls the light – beam size .

 3- Diaphragm : located beneath the stage , and function to                                   regulated light intensity passing through the                                lenses. 

C- Adjustment system

1- Coarse adjustment knob : when turned ,and lower body                                                      tube or the Stage for focusing the                                                  microscope occurred . used with                                                    4X and 10X.   

2- Fine adjustment knob :  usually found below or external the                                            coarse adjustment knob , and used                                                with high power or oil immersion                                                lenses for fine or final focusing .

D- Magnification system 

 1- Ocular lens (eye piece) : A removable lens at the tope of                                                    the body tube , marked  10X in                                                       most microscope .

 2- Scanning objective lens : A lens marked  4X in most                                                              microscope .

3- Lower power objective lens :  A lens marked  10X in most                                                        microscope .

4- High power  objective lens: A lens marked  40X in                                                                    microscope

 5- Oil – immersion objective lens :  A lens marked  100X in                                     most microscope and distinguished by an                                     colored circle – oil immersion called this                                      because it look at the objective through a                                      drop of oil ( cedar – wood oil ) .

6- Nosepiece : A plate usually circular , at the bottom of the                               body tube . 

7- Revolving nosepiece : it is a movable part of the nosepiece                                        that contain the various objective lenses .

Magnification