Microscopy

The microscope was first applied to biological material in the early seventeenth century by researchers such as Robert Hooke and Antoni van Leeuwenhoek, and remains a pivotal tool in learning about biology today.
Over the course of this year, you will be using two different types of microscope:

I - Compound (Light) Microscope

II - Stereoscopic (Dissecting) Microscope

These microscopes are delicate and expensive instruments and must be treated with care.

When using a Light Microscope please keep the following in mind:

1. When transporting your microscope always pick it up by the arm. Hold it upright and support the base with your free hand.
2. The arm supports an inclined body tube, which in turn supports the magnifying elements of the microscope. At the end of the tube is the ocular, one of the magnifying elements. The other magnifying elements are screwed into a revolving nosepiece at the bottom of the body tube; these are called objectives.
3. Underneath the body tube and nosepiece is a flat plate, the stage, upon which objects to be examined are placed. Directly beneath the stage opening you will notice a system of lenses, the condenser, which serves to concentrate the light from the illuminator below.
4. Light plays an extremely important role in the operation of a compound microscope. The critical importance of light makes necessary its careful adjustment, and several controls are available for this purpose. The iris diaphragm may be found just below the condenser lens system. This control is one of the most important on your instrument.
5. Changes and adjustments in the focus, which are necessary when an object is first placed on the microscope and essential in order to perceive depth, are accomplished by means of coarse and fine adjustment knobs usually located on the arm. Note that the fine and coarse focus knobs are separate on some of our microscopes and combined on others.

You should be able to locate the terms in bold on the image of the light microscope above, or click here if you are having problems.

Keep the following in mind when using a Stereoscopic Microscope:

1. The depth of field is much greater than with the compound microscope, which allows objects to be view in three dimensions
2. The optics do not invert images
3. To focus close your left eye and adjust the focus of the image viewed with the right eye. Open your left eye and close your right eye and adjust the focus for the left eye using the secondary focus ring located on the left ocular.
4. All of our stereo microscopes are binocular. To obtain the correct interpupilary distance for your eyes you must adjust the distance between the two oculars by gently pushing or pulling the oculars until you see the object as a single image.
5. Note that the dissecting microscope is not parfocal and must be re-focused when the magnification is changed

Consider the following questions for both the light microscope and the stereoscopic microscope

• When you move the slide to the right while looking into the microscope, which way does the image appear to move?
• Which way does the image move when you move the slide toward you?
• Away from you?

Click here to view the letter F slide as seen through a compound light microscope
Click here to view the letter F slide as seen through a stereoscopic microscope

Other Pages of Microscopy topics:

• Magnification
• Types and Images of Microscope Slides