Name: __________________________________
Course & Year: ___________________________
Group: __________________________________
Date: ___________________________________
SCORE:
ACTIVITY NO.
1
Introduction:
The compound microscope is an optical instrument that enables one to see clearly the structures that
are too small to be seen by the naked eye. It is made up of systems of lenses in varying magnifications. A set
of lenses is in the ocular or eyepiece; the other set is in the objectives. Combination of these lenses increases
the size of the object being viewed, hence, the magnifying power of the microscope.
Another attribute of the compound microscope is its resolving power. It is the ability to separate
objects and to show them in distinct views, thereby showing clear contrast between them and producing
visible image and sharp details.
A microscope is an expensive but a very essential tool in scientific studies. It must be used with care.
Objectives:
1. Become familiar with the parts and functions of the compound microscope;
2. Label the parts of the microscope; and
3. Demonstrate appreciation on the importance of microscope in the study of life.
Materials:
A compound microscope, tissue paper, or soft cotton cloth
Activity Proper:
Guided by the following text, familiarize yourself with the compound microscope and its parts. These
are grouped into three: the mechanical parts which hold the structure together and control their use; the
optical and the illuminating parts which regulate the light rays including the formation of images. Study the
movable parts and see how each functions.
A. Mechanical Parts:
1.
2.
3.
4.
5.
6.
7.
Horseshoe base – the part that supports the entire microscope
Pillar – the part that extends upwards from the base to support all other parts, and to hold the stage
Inclination hinge or joint – the portion that allows tilting of the microscope at a desired angle
Stage – the part where the object to be examined is placed
Stage clips – hold the slide securely in position
Arm – supports the body tube and primarily serves as a means for carrying the microscope
Body tube – the cylinder that bears the objectives at the lower end and the eyepiece at the upper
portion
8. Draw tube – a small tube attached above the body tube wherein the ocular or the eyepiece is placed
9. Adjustments – the wheels that raise or lower the tube
a. coarse adjustment – changes the elevation of the tube rapidly for preliminary focusing
b. fine adjustment – permits gradual changes in the elevation of the tube for final and accurate
focusing
10. Dust shield – the circular disc above the revolving nosepiece to protect the objectives from dust
particles
11. Revolving nosepiece – carries the objectives, and turns them
B. Optical Parts
1. Ocular / Eyepiece – a small tube consisting of lenses, that indicate the relative power of magnification
2. Objectives – refer to the cylindrical tubes attached to the revolving nosepiece for initial magnification
of the image
a. Low Power Objective – views the specimen in a larger field
b. High Power Objective – obtains greater magnification and views detailed structures of the
specimen
c. Oil Immersion Objective – obtains greater magnification than HPO. In using this, a drop of
oil is placed on the slide for better refraction
C. Illuminating Parts
1. Mirror – reflects light rays through the object. One side of the mirror is plain (used with natural light);
the other is concave (used with artificial light)
2. Sub-stage – the part used primarily for focusing light rays upon the specimen
a. Irish diaphragm – made up of a number of thin pieces of metal operated by a lever used for
regulating the amount of light necessary to obtain a clear view of the specimen.
b. Condenser – lens or series of lenses mounted in substage attachment for the purpose of
concentrating light upon the object to be examined. Condensers are valuable with high power
objectives and oil-immersion lenses.
Guide Questions:
I. Label the parts of the microscope.
A Compound Microscope
II. Comprehensively answer the following. Use the space below for your answers.
1. Why is compound microscope an essential tool in scientific studies?
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2. How do you carry a microscope when working in a laboratory?
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3. How far should be the microscope from the table’s edge?
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4. How would you determine the total magnification of your specimen?
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5. Why is it not advisable to lower the body tube using coarse adjustment while looking through
the eyepiece?
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III. Magnification. Fill in the following table.
Objection
OIO
LPO
HPO
Magnification
Ocular Lens
Total Magnification
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