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Electron Microscopes
Use electrons instead of light to form images.
Light Microscopes
Light Microscopes
• Unknown when first invented, but probably between 1590-1610 A.D.
• Can magnify up to 1000 x
• Shines light through an object and projects the image through a series of lenses that magnify the image.
• Relatively inexpensive
Uses
• Great for studying live microscopic organisms.
• Great for studying cells and tissues in general.
• Widely used in hospitals and clinics to diagnose disease.
Example images using light microscopes
Example images using light microscopes
Example images using light microscopes
Transmission Electron Microscope(TEM)
Transmission Electron Microscope(TEM)
• First invented in 1931 (in Germany)• Can magnify up to 200,000 x (and beyond)• Similar to a light microscope except that a beam
of electrons is used instead of light. The electrons that penetrate through the object and create an image which is then enlarged and then viewed on a computer monitor.
• Samples of the object must be sliced very thin before using the TEM. (No living specimens.)
• Very expensive and time consuming to prepare slides.
Uses of the TEM
• Used in biological/medical research to investigate parts of cells and molecules.
• Used in material science to study the structure and the weaknesses of crystals.
• Used in nanotechnology.
Example images using TEMs
Example images using TEMs
Example images using TEMs
Nanotubes
Example images using TEMs
Marburg virus
Scanning Electron Microscope(SEM)
• http://www.mos.org/sln/SEM/
Scanning Electron Microscope(SEM)
• First invented in 1942• Can magnify typically up to 10,000 x• Gives a 3D image of the surface of the object• Again, a beam of electrons is used instead of
light. The electrons that bounce off the object create the image. The microscope scans a certain region of the object multiple times and then combines multiple images to create what we then see on a computer monitor as one 3D image.
• No slicing needed so easier to prepare samples. Larger objects can be viewed.
• Very expensive.
Uses of the SEM
• Multiple uses - for viewing the surface of any microscopic object.
• Insect parts• Bacteria• Food industry• Material science• Education • Art
Example images using SEMs
•Mascara brush
Example images using SEMs
• Moth antennae
Example images using SEMs
Practice Quiz
• Now look at the following images. Determine which type of microscope produced each image and write your answers down on a piece of paper.
• LM = Light Microscope• TEM = Transmission Electron Microscope• SEM = Scanning Electron Microscope
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Mosquito
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