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A project report on microscope. This project report will help you to learn about: 1. Definition of Microscope 2. Types of Microscope 3. Components 4. Use 5. Working System 6. Measurement of Magnification.
Contents:
- Project Report on the Definition of Microscope
- Project Report on the Types of Microscope
- Project Report on the Components of Microscope
- Project Report on How to Use Microscope
- Project Report on the Working System of Microscope
- Project Report on the Measurement of Magnification of Microscope
Project Report # 1. Microscope:
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Microscope is an instrument to get an enlarged image of the object. The smallest thing visible to our naked eyes is about 1/5 of a cm or 2.2 millimetre, and that also not in details. To study smaller objects they are to be magnified. For ordinary use, the length ‘millimetre’ is quite sufficient, but this is too big for scientific studies. Instead we use the ‘μm’. ‘m’ is short for a metre, ‘μ’ is short for the word ‘micron’.
If metre is taken as the unit of length ‘μ.m’ is a millionth part of a metre (a thousand times a thousand makes a million). The microscope in which visible light is used for observation is called optical microscope. For general work optical microscopes are used.
Project Report # 2.
Types of Microscope:
i. Simple Microscope:
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It is used in field studies. It has only one lens. The magnification is about fivefold.
ii. Binocular Microscope:
In shape it is almost similar to a compound microscope, without a nose piece and it is of less height. The objectives and eye pieces are changeable. The base is either a horse-shoe or rectangle in shape.
Both the object to be studied and the microscope are placed directly on the dissecting tray in case of a horse-shoe base. In others the object is put on a small dissecting tray, placed on a thick glass plate mounted on a circular metallic frame serving as the stage. These microscopes give about ten to twentyfold magnification.
iii. Compound Microscope:
(Fig. 21.1)
Project Report # 3. Components of Microscope:
Base:
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It is a supporting stand, rests on the table and bears the weight of the microscope.
Arm (Limb):
It is a curved, solid piece, movably adjusted with the base at the inclination joint. The arm holds the body tube and the stage.
Inclination joint:
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It holds the body of the microscope with the base and permits inclination of the upper part to adjust to eye level.
Body tube:
It is a metal tube blackened inside. A revolving nose piece carrying the objectives is attached to the lower end. At the top of the body tube is screwed a draw tube which houses the eye piece.
The body tube may be:
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The straight monocular
The inclined monocular
The straight binocular
The inclined binocular
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The revolving inclined mono or binocular.
Stage:
It is a sort of squarish or rectangular platform with 10 to 1 2 cm sides and having a circular hole at the centre. It is made up of highly polished metal or bakelite and provided with two spring clips for holding the slide or a sliding bar. The stage is firmly secured with the arm.
Coarse adjustment:
It is attached to the arm. The adjustment has a large head. Clockwise turn of the pinion head moves the body tube downward and anticlockwise turn moves the body tube upward.
Fine adjustment:
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It is also attached to the arm, parallel to the coarse adjustment. It operates in the way as in the coarse adjustment, but the movement of the body tube is only slight with the turning of the pinion. Usually ten turns of the fine adjustment pinion are equal to one turn of that of the coarse adjustment.
Mirror:
A planoconcave round mirror is fitted below the stage at some distance from it. In artificial light the plain surface is used. In skylight the concave surface is used, as more light is reflected to the object from this surface. If required the mirror can be taken out from the hole in the base of the microscope and a sub-stage lamp fitted.
Illuminating apparatus (condenser):
It is fitted below the stage and provided with an iris The opening of the diaphragm can be reduced or even closed completely. The arrangement is to regulate the amount of light passing through the object.
Project Report # 4. How to Use a Microscope?
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Before using the microscope one must be sure that the mechanical parts are perfectly clean. For cleaning the mechanical parts use a soft, clean linen and for the optical parts a clean, soft silk cloth or tissue paper. Remember microscope is a costly, precision instrument and must be handled with caution.
1. Turn the nose piece to bring the low power objective lens in a line with the body tube.
2. Focus the mirror for maximum illumination of the object.
3. Clean the prepared slide and place it on the stage. Look through the eye piece and bring.
the object in the field of the microscope. Move the slide to bring the portion of the object to be studied to the centre of the field. Fix the slide with spring clips. Look through the eye piece and turn the coarse adjustment for focusing. For sharp focusing use fine adjustment.
For detailed study under high magnification, turn the nose piece to bring the objective with higher magnification in the line. Use only fine adjustment for focusing. If the light is strong, reduce it by narrowing the opening of the Irish diaphragm. If poor, arrange for a brighter source of light. Study the object.
Project Report # 5. Working System of Microscope:
The working system of a compound microscope is magnification with double lenses. The initial magnification of the objective lens is further magnified by the eyepiece, and we get the total magnification (Fig. 21.2).
If the body tube is of standard length, i.e., 160 mm, only then the total magnification is equal to that obtained by multiplying the magnification of the objective with the magnification by the eye piece. The body tube is always not of standard length and the magnification should be measured with a micro-metre.
Project Report # 6. Measurement of Magnification of Microscope:
A. To measure magnification under a microscope the tools required are an oculometre and a micrometer.
1. Oculometre:
It is a piece of thin, circular glass disc with a diameter of about 15 mm. A scale, the divisions of which are not to scale, is etched across the middle of the disc.
2. Stage micrometer:
It is a thick glass slide. A scale, divisions of which are to the scale, is etched at the middle of the slide along its long axis.
Technique:
The oculometre is put inside the eye piece by unscrewing the top part of the lens. It is screwed down again before use. The micrometer is placed on the stage of the microscope and the scale is brought to the centre of the hole of the stage.
Rotating the eye piece and also moving the micrometer the two scales are made to overlap. The divisions of the two scales are not equal, as a result perfect overlapping of lines marking the divisions of the scales appear only at a few points.
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Note the number of divisions of the micrometre (MM) which correspond to the number in the oculometre (OM). The divisions of the micrometre are always smaller than those in the oculometre. Calculate the actual measurement of a division of the oculometre.
One division of MM = 1 μm
Assuming 5 divisions of OM correspond to 10 divisions of MM
One division of OM = 10/5 or 2 μm
One div. of OM = 10/5 or 2 μm
The magnifications of both the objective and eye piece, and the particular microscope used for ascertaining the measurement of oculometre scale are to be noted for future use, as the magnification varies with lens and the microscope.
Procedure for measurement:
To measure an object put the oculometre in the eye piece. Place the slide on the stage of the microscope, focus the object, and slowly move the slide and also rotate the eye piece to bring any structure of the object with sharp outlines, against the scale in the oculometre.
Read the divisions and calculate the actual size of the structure. To know the magnification of a camera lucida drawing or a photomicrograph, measure the figure with a scale and calculate the magnification from the actual size of the object.
B. An approximate magnification of the object may be calculated using the following formula:
m = I/f × e
m = magnification
I = length of the body tube
e = magnification of the eye piece
f = focal length of the objective.
