Microscope and Other Tools in Biology

The subject of this lesson is the MICROSCOPE. The microscope is a tool used to study objects too small to be seen with the unaided eye. You will be using the microscope to discover a whole world of life too small to be seen with the eye alone. The study of the diversity of life will begin with microscopic organisms and progress to the largest organism.

The microscope enlarges the image of a small object. In your biology class, you will be using the compound microscope. It consists of two lenses, each fitted into the end of a tube within a tube.


How to Prepare the Microscope


The word microscope comes from the Greek word micro meaning “small” and scopein meaning “to see or view.” The purpose of a microscope is to magnify small objects so that they can be seen.

The microscope that you will be using is both a light and a compound microscope. The light for your microscope will come from sunlight. The word compound refers to a microscope with two lenses or a set of lenses. There are two sets of lenses in a microscope, one at each end of the body tube. The two sets of lenses are called the EYEPIECE and the OBJECTIVE.


How to Focus the Microscope


The purpose of adjusting or focusing the microscope is to produce a magnified image that is sharp. That is where the problem begins. Do not be surprised if you do not get sharp images at once.

The scientific word for focusing to get a sharp image is RESOLUTION. MAGNIFICATION is the enlarging of an image. Resolution and magnification are two different things. The problem is that you cannot get good resolution and good magnification at the same time.

A microscope may have to be continually adjusted to get a sharp picture. This is especially true when you are viewing living things. They swim up and down in a drop of water. As an organism moves in a drop of water, it will go out of focus. Turn the adjustment knob to bring the image back into focus.

The Limitations of a Microscope



    1. Resolution limits magnification.
    2. Continual focusing is necessary if the object moves.
    3. Image will be upside-down and reversed.


Next:  Microscope Parts and Their Functions