Cells are the basic unit of life.
They are sacs of fluid surrounded by membranes.
Inside the fluid float chemicals and organelles.
And we know all that due to magnifying ability of microscopes. Early microscopes did not magnify to a great extent, but nowadays, there are modern light microscopes that can magnify 1,500 times and electron microscopes that can magnify up to two million times.
Magnification is simply a function of making an object appear bigger.
The magnification of a light microscope is formed using a mixture of the powers of the eyepiece and the objective lens.
The objective lens is located at the lower end of the body tube, and usually there are several objectives, of various magnifying powers, mounted on a revolving nosepiece that allows each objective to be swung into place along the optical axis.
The magnifying power of a compound microscope is equal to the product of magnifying powers of the eyepiece and the objective.
Compound light microscopes normally have three different objective lenses to allow the slide to be viewed in three separate manners.
The objective lenses on a compound light microscope may have powers that start of as:
- 4x on the smallest power,
- 10x on the middle power setting and
- 40x on the maximum power setting.
This means that the object can be magnified either, 40x, 100x or 400x.
The magnification required to produce the visible image can be calculated using the formula:
Magnification = Image ÷ Object.
The magnifying power of a microscope is an expression of the number of times the object being examined appears to be enlarged and is a dimensionless ratio.
For example, if a specimen appeared 10mm in length under a microscope with a magnification of 1,000 times, the calculation of the actual length would be:
Length of object = 10 ÷ 1000 = 0.01 mm
Magnifying an object without increasing the amount of detail seen will not provide a good image; therefore magnification without resolution is insignificant for the spectator.
No resolution means empty magnification, so although the image will be more magnified, the resolution will remain low.
The result is unclear image, because magnification is how large the image is compared to real life, but resolution is the amount of information that can be seen in that image.
Compound light microscope has the advantage to view a variety of samples, including whole living organisms or sections of larger plants and animals, but for viewing very small things, like organelles that are within cells, nowadays science use electron microscope.