What is Microscope?
February 25, 2010
Microscope is a tool to magnify small object that cannot see with direct eyes (size 0,1 mm less).
Where microscope usually find?
We can find microscope in elementary until high school, university, or every places who have laboratory especially science laboratory. Include biology. Biology is study about living things and all factors.
Microscope components
The components are divide into two major groups. optical and non-optical parts.
Optical parts : ocular lens and objective lens.
Non-optical parts : arm, object stage and base.
Take a look picture above :
1. Ocular
2. Tube
3. Coarse adjustment knob
4. Fine adjustment knob
5. Revolver
6. Objective lens
7. Arm
8. Object stage
Ocular , eyepiece, is a complex piece, located at the top of the instrument (usually has a magnification of 5,10, 15)
Objective lens, usually present on a rotatable nosepiece or revolver, which make it possible to move them into position over a slide. Magnification depends on maker factory. Usually have magnification of 4, 10, 40 and 100.
Object stage, stage to put object
Condenser, merge of lenses to collect light.
Diaphragm, to arrange light intensity. In simple microscope only found diaphragm without condenser.
Mirror, has two side, plate and concave side. Use to reflect light from source light.
Fine Coarse adjustment knob, locate in arm use to arrange objective lens position to the object.
Types of Microscope
There are two kinds of microscope, light and electrical microscope. Light microscope divide into different types: brightfield, darkfield, phase-contrast and fluorescent microscope. Brightfield microscope is type that usually found in school practice.
Brightfield microscope is A microscope that allows light rays to pass directly through to the eye without being deflected by an intervening opaque plate in the condenser. Common type that usually used is type which has two or more lenses like ocular and objective lenses to magnify object.
Brightfield microscope has many oculay types: monocular, binocular and trinocular. Lightsouces of the microscope are various (using sunlight or lamp). In trinocular microscope, we can display our observation into camera or television. For further information, click here.
Work principles
Total magnification is magnification in objective times magnification in ocular. For example : objective: 40x, ocular: 10x , total magnification 40x10=400. For light reflection principles in microscope, click here.
When using 100x objective lens, we have to open fully diaphragm and condenser to get optimal light. In 100x magnification we need to use immersion oil to avoid difference refractive index between air and glass. Refractive index of air : 1, and refractive index of glass : 1,56. Immersion oil has same refraction index with glass. Watch this picture to see diffraction process.
