Kamis, 16 Agustus 2012

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Observation of Cell with Microscope and Microscopic Measurement

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Cell has microscopic structure. Observation and measurement of microscopic structure require microscope device and micrometer.

 1. Microscope
The Parts Of a bright field Microscope


Microscope can be distinguished two large group based on the light source (illumination), which are light microscope and electron microscope. Light microscope includes bright field, dark, field, phases contrast optics, and fluorescence. Electron microscope has two types, transmission and scanning electron microscope.
Light microscope has two positive lenses, objective, lens, and ocular lens, Objective lens is the lens closest to specimen (object) while ocular lens is the lens closest to eye. Objective lens produces real image that is projected and magnified by ocular lens to create and magnified by ocular lens to create optical image which our eyes can see.

Generally,  Microscope has three objective lenses with 10x, 45x, and 100x magnification. Multiplication of objective and ocular magnification truns out to be the total magnification of microscope
The light source of bright field microscope is sun light or electric bulb. To focus the light , microscope is equipped with mirror. A plane mirror is usually used in microscope using lamp as their light source, while a concave mirror is used in  microscope using no condenser

2. Microscopic Measurement

a. Ocular micrometer
b. Stage micrometer
c. calibration result of ocular and stage micrometer
The size and shape of a cell are very useful in indication or classification of micro organism. The measurement of cell diameter is made by inserting ocular micrometer in ocular lens that will be used. Before it is used, ocular micrometer is firs stamped on stage micrometer that has definite scale. To have better understanding, do the following experiment!.

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