Microscopy: Types, Principles, and Microscope Parts

MICROSCOPE

It is a laboratory instrument used to examine objects that are too small for the naked eye.

Microscopy

It is the science of investigating small objects and structures using a microscope.

Microscopic

Objects, specimens that are invisible to the eye unless aided by a microscope.

Magnification

Is the factor by which an image appears to be enlarged, the image formed is enlarged to a particular degree called the 'Power of Magnification'.

Power of Magnification

Examples include magnification levels of 50x, 100x, 200x, 400x, 630x, and 1000x.

Depth of Field

Refers to the distance that you can move the specimen and still maintain the focus.

Resolution

It is also called resolving power. It refers to the ability of a lens to show two adjacent objects as discrete entities.

Light Microscope

Use compound lenses and light to magnify objects. The lenses bend or refract the light, which makes the object beneath them appear closer.

Application of Light Microscope

1. Cellular and tissue analysis 2. Examine blood samples, body fluids, and tissue biopsies 3. View and differentiate bacteria 4. Inspecting the quality of materials.

Scanning Electron Microscope (SEM)

A type of microscope that allows scientists to view much smaller objects with a light microscope. SEMs don't use light waves; they use electrons to magnify objects up to 2 million times.

Application of Scanning Electron Microscope

1. Examining microscopic evidence such as fibers, tool marks, gunshot residue, and soil samples. 2. Examining biological samples and animal tissue. 3. Performing quality checks on pharmaceutical products. 4. Ensuring manufactured goods meet specific standards by identifying flaws and contaminants.

Transmission Electron Microscope (TEM)

A type of microscope that also uses electrons, but instead of scanning the surface the way SEMs do, electrons are passed through very thin specimens.

Application of Transmission Electron Microscope

1. Identifying and classifying viruses and bacteria, including diagnosing infections and studying viral agents. 2. Investigating crystalline structures, internal fractures, and defects in materials. 3. Visualizing the structure of protein molecules and cell membranes.

Eyepiece

The lens you look through magnifies your specimen 10x.

Body Tube

Supports the eyepiece.

Nose piece

Holds the objective lenses.

Arm

Supports the body tube.

Objectives

Magnify by different powers: Low Power Objectives - 4x, Medium Power Objectives - 10x, High Power Objectives - 40x.

Stage Clip

Holds the slide in place.

Aperture

Allows light to show through.

Stage

Supports the slide being used.

Diaphragm

Controls the amount of light passing through the opening of the stage (light adjustment wheel).

Course adjustment knob

Moves the body tube up and down for focusing.

Fine Adjustment Knob

Moves the body tube up and down for finer focusing, high power.

On/Off Switch

Turns the microscope on or off.

Base

Supports the microscope.