Compound microscopes use two lenses to magnify a specimen, whereas light microscopes use only one lens. Another major difference between compound microscopes and light microscopes is their power source. Compound microscopes use electricity to illuminate an object, whereas light microscopes simply use sunlight or some other external lighting source. It's important to know the difference between the two before beginning an experiment.
Basics
Light microscopes, also known as optical microscopes, are the simplest and oldest type of microscope. Light microscopes usually consist of two simple lenses that focus light in such a way to magnify small objects. One of the most common types of light microscopes is the basic magnifying glass. Light microscopes are used for simple magnification tasks.
The compound microscope is used for more in-depth magnification, such as examining tiny objects like bacteria. The compound microscope works in a similar manner, except the compound microscope uses more than two lenses. The extra lenses allow for much more magnification than the basic light microscope.
Lenses
Light microscopes by definition consist of any device that uses a lens to magnify an image.
Compound microscopes consist of at least two pairs of lenses. The lens closest to your eye when you're looking through the microscope is called the ocular lens. Ocular lenses normally magnify an object to around 10x. Check the lens tube for your particular microscope's magnification.
The second lens (or set of lenses) is called the objective lens, and this is the lens closest to the stage where the slide sits. There are normally a few objective lenses mounted onto a revolving piece, which can be easily rotated to change the magnification.
Function
The light microscope works by bending light rays coming from a smaller image through a lens with a small focal length and reproducing an enlarged version of a specimen. This allows for a closer look at the specimen.
Similarly, the compound microscope's objective lens is extremely high powered with a very short focal length, much like a magnifying glass. The objective lens is lowered toward the specimen and sends an enlarged image of the specimen through the microscope tube. This is the image seen through and further magnified by the ocular lens.
Advantages and Disadvantages
Light microscopes are good to use in places far away from electricity, such as out in a forest or park. Compound microscopes are more beneficial in laboratory settings, and can be used anytime during the day or night. Because compound microscopes generate their own light source, they are also not affected by rain or cloudy weather like a simpler light microscope would be.
Verdict
Probably the most important technical difference between compound and light microscopes is that compound microscopes only allow a person to see a magnified and reproduced image of the specimen. Light microscopes, on the other hand, allow a person to view the specimen itself. Compound microscopes are generally preferred over light microscopes largely because the extent of field is much greater than the extent of field offered by single-lens light microscopes of the same magnification power.
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