microscopy

• what is magnification?

  number of times bigger an image appears compared to the size of the real object
• what is resolution?

  smallest distance between two objects that can be distinguished
• how does a light microscope work?

  passes a beam of light through a specimen which travels through the eyepiece lens, allowing the specimen to be observed
• advantages of light microscopes

  • inexpensive
  • easy to use
  • portable
  • observe both living & dead specimens
• disadvantage of light microscopes

  limited resolution
• how does an electron microscope work?

  uses a beam of electrons which are focused using magnets. the electrons hit a fluorescent screen which emits visible light, producing an image
• why is an electron microscope better than a light microscope?

  higher magnification & resolution
• why do electron microscopes have better magnification & resolution?

  the beam of electrons has a shorter wavelength than protons of light
• how has electron microscopy increased understanding of sub-cellular structures?

  • allow sub-cellular structures to be seen in detail, like the internal structures
  • enable scientists to develop more accurate explanations abt how cell structure relates to function
• what formula would be used to calculate magnification, using real size and image size

  magnification = size of image / size of real object