The light microscope is a device that uses visible light and a series of lenses to produce an enlarged image of an object.

A light microscope contains a minimum of two lenses. The eyepiece is called the ocular, and the lenses above the stage are called object lenses. It is important that the light beams are accurately transmitted and aligned between different lenses and mirrors.

When using the microscope, care must be taken to avoid damage to the device and sample, and to optimize the appearance of the subject. Make sure your desktop is sturdy enough to avoid vibrations and other movements when looking at small objects. Carry the microscope by holding its from its base and its arm.

1. Make sure that the shortest lens (lowest magnification) in your microscope points perpendicularly down. If necessary, rotate the lens dial.
2. Put your specimen on a slide and place a cover glass above it before placing the microscope slide on the stage. Fasten it with stage clips.
3. Switch the light on.
4. Look through the eyepiece to see if the specimen appears in the centre of the view. If necessary, move the slide.
5. Turn the coarse adjustment knob until the image comes into focus.
6. If necessary, use the fine adjustment knob to focus the image further.
7. Once the view is in focus, turn the revolving objective turret/nosepiece so that the lowest power objective lens is clicked into position. Use only the fine adjustment for focus.
8. To study very small objects you can turn the revolving objective turret/nosepiece again, note that the lens is now very close to the slide or may be attached to it. Therefore, you have to be very careful when focusing the microscope!