We live with numerous fascinating microorganisms, out of which many are discovered, and a lot is in the process! Technology paved the way for microscopes, and its invention helped us examine various organisms like staphylococcus bacteria, viruses, and other parasites. Now which microscope fits your use depends all on the specimen you are observing. Today we will differentiate between light and electron microscopes.
Both these microscopes have different worth in the field of technology where they are playing their roles. The key purpose of using a light or electron microscope is to magnify the images that a human eye cannot see. A light microscope utilizes a beam of light to observe tiny microorganisms like mitochondria, whereas an electron microscope uses a beam of electrons to enlarge a minuscule specimen.
Let’s have a brief overview of these microscopes through a comparison chart, and move towards details.
|Basis of Comparison||Light Microscope||Electron Microscope|
|Other Name||Optical Microscope||Beam Microscope|
|Principle||Light waves are absorbed||Electrons are scattered or transmitted|
|Chemistry of Microscope||Light & Small||Heavy & Large|
|Vacuum||No use of vacuum||Processes under vacuum|
|Type of Specimen||Can be living or non-living, stained or unstained||Only stained and non-living|
|Resolving Power||0.2 um||0.2 nm|
|Image Color||colored images formed||Black & white, grey images formed|
|Radiation||Radiations not used||Radiations used & can be leaked|
|Filaments Used||No filaments||Tungsten filament|
Light Microscope – Definition & Description
Equipment that uses light rays to magnify an object is called a light microscope or Optical microscope. Such microscopes are built with the most common parts: an eyepiece, fine focus, coarse focus, tube, nose piece, stage clips, mirrors, diaphragm, objective, objective lenses, and a condenser. This technical equipment can instantly enlarge a specimen through a light source, glass lenses, and a projection screen. Schools, colleges, and universities usually keep light microscopes for student use as these are easy to handle.
A few terms related to the microscope play a key role in clearly magnifying a tiny object. These are the magnification, resolving power, lenses employed, and the eyepiece to view an object. In a microscope, resolving power is inversely proportional to the distance between two miniature objects. Hence, a light microscope with the greatest resolving power can distinguish two very closely placed specimens.
Light microscopes can be categorized into simple and compound microscopes. As the name indicates, a simple microscope uses only one lens (magnifying glass), while a compound microscope uses different lenses to amplify an object.
Types of Light Microscope
There are different types of light microscopes available mentioned below:
- Dark Field Microscope
- Bright Field Microscope
- Fluorescence Microscope
- Confocal Microscope
- Phase Contrast Microscope
- Differential Interference Contrast Microscope
- Ultraviolet Microscope
Electron Microscope – Definition & Description
It was discovered in 1920 that electrons traveling in a vacuum behave like light and go straight in the path. These led to the invention of the electron microscope. A modified form of light microscope uses a specific beam of electrons to view microscopic objects. Scientists now prefer using this microscope in big research labs to get enhanced results of small entities and get their detailed characteristics.
First, a microscopic chamber is taken to detect a specimen, and all of its air is pumped out to make it a vacuum. After placing the object at the bottom, a beam of the electron is pushed down the chamber from where it strikes different attached mirrors. The beam then falls on the particular specimen point, which is to be focused. It passes over the entire object to magnify it with the help of an electron detector. When the object is completely magnified, it is shown on the display/screen.
Types of Electron Microscope
Similar to a light microscope, an electron microscope also has different types, such as:
- Transmission Electron Microscope (TEM)
- Scanning Electron Microscope (SEM)
- Scanning Transmission Electron Microscope
- Focused Ion Beam and Electron Microscope
Difference between Light and Electron Microscope
We have mentioned the key differences between the two microscopes below:
It is also known as an Optical Microscope.
It is also known as a Beam Microscope.
A Dutch spectacle-maker, Zacharius Jansen, is believed first to invent the light microscope in the late 1590s. He, along with his father Hans from Holland, contributed to its making.
On the other hand, the electron microscope was invented in 1931 by Physicist Ernst Ruska and German engineer Max Knoll.
Source of Illumination
This microscope uses a beam of light (visible) of 400-700 nm wavelength to amplify tiny objects.
This microscope uses a beam of electrons (charged particles) of wavelength approx—1 nm to amplify tiny objects.
Composition of Lenses
In a light microscope, every lens (be it objective, condenser, or eyepiece) is made up of quartz or glass.
The entire lens system in an electron microscope contains electromagnets rather than glass.
Magnification & Resolving Power
It comes with approximately 1000X-1500X magnification power and a resolution of 0.2 um.
On the contrary, an electron microscope has almost 1,000,000X magnification with a resolving power up to 0.2 nm.
Types of Screens Used
A light microscope uses glass lenses and a projection screen to detect an object.
On the other hand, an electron microscope uses an electromagnetic and a fluorescent screen to amplify tiny objects.
Nature of Magnified Result
The results obtained from a light microscope are live and natural colored.
An electron microscope shows a 3-dimensional, black & white image of the specimen.
View of the Image Formed
One can directly view the magnified image through the eyepiece of a light microscope.
An amplified image from an electron microscope is observed on a zinc sulfate fluorescent screen or a photographic plate.
This microscope doesn’t utilize any filament to examine a tiny object.
An electron microscope uses tungsten filament to generate electrons.
It is less expensive equipment with more availability and is also easy to operate.
It is a bit complex microscope which is expensive and difficult to handle.
Which One to Prefer?
Now that you know the differences between light and electron microscopes, it wouldn’t be difficult to choose between the two. Before utilizing any microscopes, understand the analyzing criteria and what organism you want to magnify. An electron microscope is comparatively expensive and tricky to use, so educational institutes and clinics usually prefer a light microscope.