STUDY OF THE MICROSCOPE AND ITS PARTS
Objective: to familiarize oneself with the parts
and functions of a microscope and develop skills in using a microscope for
microscopic observations.
Theory: Microscopes are essential
tools used in scientific research and various fields of study. "Micro"
refers to tiny, "scope" refers to view or look at. Microscopes are
tools used to enlarge small objects to be observed and studied. Microscopes
range from a simple magnifying glass to the expensive electron microscope. They
enable the visualization of objects that are too small to be seen by the naked
eye. A typical compound microscope consists of several parts, including an
eyepiece, objective lenses, a stage, a condenser, and a light source. The
eyepiece magnifies the viewer, while the objective lenses offer different magnification
levels for the specimen. The stage holds the specimen in place, and the
condenser focuses light onto the specimen. By adjusting the focus and observing
the specimen under different magnifications, one can gather valuable
information and make detailed observations.
The microscope operates on the
principle of magnification and resolution:
Magnification: The process of enlarging the apparent size of an object.
Resolution (Resolving Power): The ability to distinguish two closely spaced points as separate entities.
The total magnification of a microscope is given by:
Total Magnification=Objective Lens Magnification × Eyepiece Magnification
For example, if the objective lens has a magnification of 40x and the eyepiece has 10x, the total magnification is 400x.
Based on the working principle, microscopes are of the following types.
1. Compound
microscope
2. Specimens
(e.g. prepared slides)
3. Lens
paper or a clean cloth
4. Pen
or marker
Procedure:
1. Set
up the microscope on a clean, sturdy surface near a power source, ensuring
proper illumination.
2. Clean
the microscope lenses (eyepiece and objectives) using lens paper or a clean
cloth.
3. Place
the prepared slide on the microscope stage and secure it using the slide
holder.
4. Start
with the lowest magnification objective (e.g.10x) and position the slide on the
stage.
5. Look
through the eyepiece and adjust the focus using the coarse and fine adjustment
knobs until the image becomes clear.
6. Observe
the specimen, noting any structures or features of interest.
7. Switch
to higher magnification objectives (e.g., 40x or 100x) to observe the specimen
in more detail.
8. After
completing the observations, turn off the microscope and clean the lenses
before storing it properly.
Result:
Draw a well-labelled diagram of a microscope
Through this practical activity, we successfully studied the microscope and its
functionalities. We gained hands-on experience in preparing slides, adjusting
magnification, and observing specimens under a microscope. The microscopic
observations allowed us to visualize and appreciate the intricate details of
various specimens. The skills acquired during this exercise will be beneficial
for future scientific endeavors that involve the use of a microscope.
Precautions:
· Always hold the microscope with both hands—one on the arm and the other supporting the base.
· Ensure the microscope is on a flat, vibration-free surface to avoid slipping or shaking.
· Use only lens paper (not tissue or cloth) to clean objective and eyepiece lenses.
· Avoid touching the lenses with your fingers.
· Always begin with the lowest objective lens (10x) to locate the specimen before switching to higher magnifications.
· After use, lower the stage and switch to the lowest objective lens to avoid damage.
· Prevent overheating by switching off the light source when not in use.
· Always cover the microscope when not in use to prevent dust accumulation.
· Store in a dry place, as humidity can cause fungal growth on lenses.
References:
Cappuccino, J. G., & Welsh, C. (2018). Microbiology: A laboratory manual (11th ed.). Pearson.
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