Electron microscopes use “dancing” electrons rather than light to illuminate an object or sample. First developed in 1931 in Germany for laboratory use, it was not until 1965 that electron microscopes were available commercially. The first electron microscopes were produced by RCA.
So what kinds of things can you see with electron microscopes? Electron microscopes can reveal the following information.
- 1. Topography-What does the surface of the object or sample look like? Is it smooth? Rough? Hairy? Hard or soft?
- Morphology-What are the shapes of the particles that make up the sample? Are they round, oval, square, triangle, or hexagonal? Is it made of strong or weak particles?
- Composition-What elements or compounds is the object made of? Does it have oxygen or hydrogen in it? What is its’ melting point or freezing point?
- Crystallographic Information-What does the arrangement of the atoms look like? What are its properties?
Electron microscopes are capable of magnifying an object or sample up to one million times. This magnification allows scientists to use the electron microscopes to distinguish individual molecules.
How do electron microscopes work?
Electron microscopes work in the same way as lighted microscopes except that instead of light, electrons “dance” across an object or sample and illuminate it.
Due to this beam’s strength, fine detail can be seen including variations in its surface and what it is composed of. A vacuum is used to speed up the electrons until their wave-length is shorter than that of white light. The shorter wave-length allows higher resolution which results in fine detail.
These “dancing” electrons are then focused upon the object or sample and they form an image on the photographic plate. Although electron microscopes are quite advanced, one of the drawbacks to their use is that it cannot show movements that occur in living cells because of the high vacuum that is necessary to cause the electrons to pass across the sample.
There are two different kinds of electron microscopes.
- The Transmission Electron Microscopes or TEM’s create an image by passing electrons through the object or sample.
- The Scanning Electron Microscopes or SEM’s give more of a 3D look of an object or sample and the magnification is shown on a television screen which gives more depth detail.
To impress your friends with your knowledge of electron microscopes you need to learn just a few things.
First, electron microscopes use beams of electrons to illuminate an object or sample rather than light. Secondly, electron microscopes can magnify an object or sample up to one million times which shows great detail. And lastly, electron microscopes are used by scientists, engineers and many others.