Microscopes - Light and Electron
Transmission Electron Microscope (TEM)
Mainly used for studying internal structures of cells. Image created is 2-D. Electromagnets magnify the image by passing a beam of electrons through a thin specimen.
Resolving power
Measurement of the clarity of an object
Electron Microscope
A microscope that uses a beam of electrons instead of light to magnify objects up to 500,000 times actual size. Electron microscopes have a much higher resolving power (higher clarity) than light microscopes because of the use of electrons instead of light. Electron microscopes allow scientists to view structures within a cell. Electron microscopes can only view dead specimens. Two types of electron microscopes: 1. Scanning Electron Microscope (SEM) 2. Transmission Electron Microscope (TEM)
What is the disadvantage of an electron microscope?
Because it cannot be used to view live specimens.
Why can you not use electron microscopes to view live specimens?
Because the process used to prepare the specimen to be viewed would kill the specimen.
What type of microscope would you use to view the larger cells of plants and animals?
Compound light microscope
What type of microscope would you use to view an organ that does not require much magnification?
Dissecting microscope
What type of microscope would you use to view viruses, molecules, atoms, proteins, and the smallest bacteria?
Electron microscope
Robert Hooke
Invented the compound light microscope. Viewed a slice of cork made of empty chambers which he called "cells."
Antone Van Leeuwenhoek
Invented the single-magnifying lens microscope. First to view microscopic cells: blood and bacteria
What type of microscope would you use to view minute details of the surface of a leaf?
Scanning electron microscope
Dissecting Microscope
The dissecting microscope is a light microscope that uses low magnification. Magnifies up to 40x. The dissecting microscope is used to view larger organisms, organs, tissues, and small objects that can be seen with the naked eye but need more magnification to view details.
What is the advantage of using an electron microscope instead of a light microscope?
The electron microscope gives much higher clarity of the specimen being viewed than the light microscope can; therefore, internal structures of cells can be viewed in much more detail.
Compound Light Microscope
The most commonly used. Magnifies from 40x up to 1,000x. Specimens can be dead or alive. The compound light microscope can be used with a dye on the slide to view tissue samples, blood, microorganisms in pond water, microscopic cells. The microscope allows light to pass through a specimen and uses two lenses to form an image.
What type of microscope would you use to view a cell's internal structures?
Transmission electron microscope
Scanning Electron Microscope (SEM)
Useful for studying details of a specimen's surface. Image is in 3-D. An electron beam passes over the specimen's surface and displaces electrons, which are then focused on a screen to form an image. Uses a conductive material (gold metal) on the specimen.
