• Created by: Freja
  • Created on: 12-04-21 11:32
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  • Microscopes
    • Resolution- the ability to see individual objects as separate entities
    • Magnification- how many times larger the image is than the actual size of the object being viewed
    • Magnification= image size /actual size
    • Types of Microscope
      • Light microscopes
        • Magnification = x2000
        • Small and inexpensive
        • No vacuum required, so can see living and dead specimens
        • Produces colour images
        • Has a simple complex preparation, so there is usually no distortion
        • Resolution = 200nm
      • Laser Scanning Confocal Microscope
        • The specimen is usually tagged with a fluorescent dye, and a laser is moved across the specimen
        • The pinhole means that any out-of-focus light is blocked, so the microscopes produce a much clearer image than a normal light microscope
        • They can be used to look at objects at different depths in thick specimens
        • Has a high resolution and a high magnification
        • Only light radiated from very close to the focal point is detected  and the detected image is projected onto a computer
        • Can produce 3D images
      • Electron Microscopes
        • Use beams of electrons to form an image
        • Have a higher resolution than light microscopes, so they give a more detailed image
        • 2 types
          • Transmission Electron Microscope
            • A beam of electrons is transmitted through a specimen
            • Denser parts of the specimen absorb more electrons, which makes them look darker
            • Has the best resolving power of 0.5nm
          • Scanning Electron Microscope
            • A beam of electrons is sent across the surface of a specimen and the reflected electrons are collected to produce a 3D image
            • Has a resolving power of 3-10nm
            • Shows the surface of the specimen
        • Magnification of up to x500000
        • Due to greater magnification and resolution, electron microscopes enable you to see the ultrastructure of cells
        • The beams of elctrons have a wavelength of less than 1nm
    • Units of measurement
      • cm to mm = x10
      • mm to um = x1000
      • um to nm = x1000


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