Lesson 3: Attention to Detail

Most life forms on planet earth are too tiny to see with the naked eye. So it stands to reason that before we can  begin to observe them we’d better learn to actually SEE them…and in order to do that we will need to learn to use a microscope.  Study this diagram, and then read about the function of each part: 

 

The OCULAR LENS (or eyepiece) is for looking through. It contains a magnifying lens which usually magnifies your specimen to a size ten times larger than it really is.

The BODY TUBE connects the ocular lens to the objectives and keeps out excess light, which makes the sample easier to see.

The REVOLVING NOSEPIECE holds the objectives.  It rotates so you can change the objective you want to use, which adjust the levels of magnification.

The ARM is for carrying the microscope.  To carry it properly, hold the arm with one hand and support the microscope under its base with the other.

The OBJECTIVES are the lenses that magnify the object.  There are usually three or four.  If your microscope has three, the usually magnify the image to 10 times, 40 times, and 100 times its normal size.  But remember that the ocular lens is also magnifying the image.  To find out the total amount the object’s size is being magnified, you multiply the power of the eyepiece (usually 10) by the magnification of the objective you are using.  So for looking at a human hair under the lowest power objective, on most miscroscopes the image is magnified 100 times its actual size (10 for the eyepiece x 10 for the low power objective).

The STAGE is where you place your slide – the glass plate on which the sample you are studying is prepared.

The STAGE CLIPS hold the slide in place.

The COARSE ADJUSTMENT KNOB is for focusing your image.

The FINE ADJUSTMENT KNOB is also for focusing.  Focus with the coarse adjustment knob first, and use the fine adjustment knob to make the focus perfect.

The DIAPHRAGM opens and closes to control how much light is allowed to light up the sample you are observing. 

The LIGHT SOURCE is under the stage.  It illuminates the sample to be examined.   It can be either an electric or battery operated light bulb or a mirror which reflects room light. 

The BASE supports the microscope.

 Study up, and when you think you have all the parts memorized try this quiz:  (click on the blue buttons to check yourself)

HOMEWORK –  CLICK HERE, print, answer the questions, and color.  If you have trouble printing the document from the page, hit the “contact” envelope to the right and let me know and I will send you the homework by email as an attachment.  You can send your answers to me for grading if you’d like.