The term "light microscope" is a general term that needs a bit of clarification. Just about all microscopes use a light source to illuminate the sample or specimen. This is why they are called light microscopes.

There are several types of light microscopes including simple (single lens) optical microscopes, compound (several lenses) microscopes, stereomicroscopes and digital microscopes. Light microscopes have varying levels of magnification available. With the exception of the stereomicroscope, these usually have a magnification range somewhere between 20X and 1500X. The stereomicroscopes have a lower magnification range of between 20X and 200X due to the fact that they are used primarily to study the surfaces of larger specimens.

In a nutshell, here is a list of the parts of a light microscope.

1. The base is just that: a base that the microscope stands on and allows it to be free standing.

2. The stage is where the sample or specimen slide is placed. There are two metal clips that hold the slide in place.

3. On the stage is a small opening in the center called an aperture. The sample is situated over the aperture for viewing and is held by the clip son the stage.

4. Below the stage is the light source. This is simply a small light bulb that shines upwards through the aperture, thus illuminating the sample. Some microscopes have a diaphragm in the stage that controls how much light is passed through the aperture. NOTE: Stereomicroscopes use two light sources to produce a 3D image to the viewer. The light source can be situated above the stage as in the case of digital microscopes. These microscopes are called inverted microscopes.

5. Directly above the stage is the nosepiece that contains the lenses used to magnify the sample. The nosepiece holds the lenses. The nosepiece rotates so the viewer can select the one they want to use.

6. The lenses, also called objectives, are held by the nosepiece and have different magnification powers, usually from 2X to 15X or 20X.

7. The arm seems to connect the base to the upper parts of the microscope. It is used to carry the microscope.

8. The coarse adjustment knob is located on the side of the microscope. It is used to focus the sample. This knob can move either the stage or the upper parts of the scope.

9. The fine adjustment knob is also located on the side of the scope. This is used to fine-tune the focus after the coarse adjustment has brought the sample into view.

10. The body or tube holds the eyepiece(s) and connects it to the nosepiece lenses.

11. The eyepiece is what you look into. The eyepiece has a magnifying power of approximately 10X.

So now you know all the parts of the microscope, you can intelligently tell your friends all about it. Knowing what the microscope's parts are helps the user to be more comfortable their first time out. It also helps if you need to order replacement parts later on.