A microscope is a crucial tool in many scientific disciplines, including biology, geology and the study of materials. Understanding the mechanism and use of a microscope is a must for many scientists and students. Microscopes work by expanding a small-scale field of view, allowing you to zoom in on the microscale workings of the natural world.
Magnification on a Microscope
Magnification on a microscope refers to the amount or degree to which the object observed is enlarged. It is measured by multiples, such as 2x, 4x and 10x, indicating that the object is enlarged to twice as big, four times as big or 10 times as big, respectively.
For a standard light-based microscope, you can get magnifications up to 1,500x ; beyond this, objects under view become excessively fuzzy because the wavelengths of light limit the clarity of images. Electrons, on the other hand, have much shorter wavelengths; according to Auburn University, electron microscopes produce useful images with magnifications up to about 200,000x.
Magnification and Distance on a Microscope
The magnification on a microscope must be adjusted carefully in proportion to distance. For optical microscopes, the higher the magnification, the closer the lens must be positioned to the object being observed. If the lens gets too close, it may crash into the specimen, destroying it and possibly damaging the lens, so exercise great care when using magnifications over 100x. Most microscopes allow for adjustment of the lens-object distance, as well as providing preset default positions that place the higher magnification lenses closer to the slide.
Measuring Magnification of a Microscope
The magnification of a microscope is measured by placing an object of known length, such as a ruler, beneath the lens and measuring the degree to which the microscope enlarges the image. You can use a similar procedure to get an idea of the scale of any magnification by putting a ruler or another familiar object, like a dime or paperclip, underneath the lens with the object on the slide. Looking through the microscope, you can compare the observed object with the relative size of the ruler.
Finding and Adjusting a Microscope's Magnification
The magnification is adjustable on both the eyepieces and lenses of most microscopes. You can check the lens extensions of your microscope to determine the magnification, which is usually printed on the casing of the lens extension. The most common lens magnifications for typical laboratory microscopes are 4x, 10x and 40x, although alternatives of weaker and stronger magnification exist.