Microscope: instrument that magnifies small objects that cannot be seen by naked eye. Microscope: instrument that magnifies small objects that cannot be seen by naked eye. * Microscope can be divided into 2 kinds: * Microscope can be divided into 2 kinds: -simple microscope : consist of one lens (ocular lens) -simple microscope : consist of one lens (ocular lens) - compound microscope: consist of 2 lens (ocular +compound lens) (light microscope+electron microscope) - compound microscope: consist of 2 lens (ocular +compound lens) (light microscope+electron microscope)

*Light microscope can be divided into: *Light microscope can be divided into: bright field\dark field\phase contract \fluorescent microscope bright field\dark field\phase contract \fluorescent microscope

*Part of microscope: *Part of microscope: 1- ocular lens(eye piece): first lens element in microscope, it will show the final image 1- ocular lens(eye piece): first lens element in microscope, it will show the final image 2- body tube : connect the objective lens with ocular lens 2- body tube : connect the objective lens with ocular lens 3- rotating nosepiece: carry the objective lens 3- rotating nosepiece: carry the objective lens

4- objective lens: magnify the specimen 4- objective lens: magnify the specimen 5- stage: support the slide 5- stage: support the slide 6- mechanical stage: move the slide horizontally and vertically 6- mechanical stage: move the slide horizontally and vertically 7- condenser: focus the light onto the specimen+control the amount of light 7- condenser: focus the light onto the specimen+control the amount of light

8- iris diaphragm: control the amount of light 8- iris diaphragm: control the amount of light 9- coarse adjustment: get the picture out 9- coarse adjustment: get the picture out 10- fine adjustment: make the picture clear 10- fine adjustment: make the picture clear

* Lenses and total magnification: * Lenses and total magnification: - the magnification of the specimen depend on two lens system in light microscope: - the magnification of the specimen depend on two lens system in light microscope: 1) ocular lense 2) objective lens 1) ocular lense 2) objective lens - ocular lens magnify the specimen 10x - ocular lens magnify the specimen 10x

- objective lens can be divided according to their magnification power into : - objective lens can be divided according to their magnification power into : 10x(yellow)40x(blue)100x(white) (oil objective lens) (why?) 4x(red) -what is the use of oil?

*Total magnification = *Total magnification = mag. of ocular lens x mag. Of objective lens mag. of ocular lens x mag. Of objective lens *Working distance: distance between the objective lens and the slide *Working distance: distance between the objective lens and the slide - as the objective lens power increase the working distance decrease - as the objective lens power increase the working distance decrease

1) bright field microscope: 1) bright field microscope: - Source of illumination is light - Source of illumination is light - The specimen must be stained - The specimen must be stained - We can see shape,arrangement, size, color of m.o - We can see shape,arrangement, size, color of m.o - We cannot see viruses - We cannot see viruses - Specimen darker than background - Specimen darker than background

2) Phase contrast: 2) Phase contrast: -Widely used to view the unstained living specimen by increasing the contrast between the object and background,and this happen according to special condensers -Widely used to view the unstained living specimen by increasing the contrast between the object and background,and this happen according to special condensers -No need to stain the specimen -No need to stain the specimen -Specimen darker than background -Specimen darker than background

3) Dark field microscope: 3) Dark field microscope: -Different from bright field or phase contrast microscope -Different from bright field or phase contrast microscope - Use special condenser with blocking disk - Use special condenser with blocking disk - No light will pass into the objective lens if there is no specimen on the stage - No light will pass into the objective lens if there is no specimen on the stage

-Objects or particle on the stage will reflect the light into the objective lens and appear as bright object on a black background -Objects or particle on the stage will reflect the light into the objective lens and appear as bright object on a black background - No need to stain the specimen - No need to stain the specimen

4) Fluorescent microscope: 4) Fluorescent microscope: - the specimen must be stained with fluorescent dye - the specimen must be stained with fluorescent dye - source of illumination is u.v light - source of illumination is u.v light

* Electron microscope: * Electron microscope: - Source of illumination is beam of electron - Source of illumination is beam of electron - We can see viruses - We can see viruses - 2 kind of electron microscope: - 2 kind of electron microscope: 1) scanning E.M: 1) scanning E.M: look at the surface of bulk object by scanning the surface with fine electron beam and measuring the reflection look at the surface of bulk object by scanning the surface with fine electron beam and measuring the reflection

2) Transmission E.M: 2) Transmission E.M: - Passes electrons completely through sample - Passes electrons completely through sample - It can obtain detailed information of the sample - It can obtain detailed information of the sample