Microscopy

• Magnification is how much bigger we can make an object appear
• Resolution is the ability to distinguish between two points
• total magnification =

  magnification of eyepiece lens x magnification of objective lens
• magnification =

  size of image (in mm) / size of real object
• Advantages of light microscopes

  Cheaper

  Easier to use

  Portable

  Can view live specimen
• Disadvantages of light microscopes

  Lower magnification

  Lower resolution

  Cannot visualise sub cellular structures
• Two types of electron microscopes

  Transmission electron microscope (TEM)

  Scanning electron microscope (SEM)
• Electron microscopes have a greater resolution and magnification because

  They use beams of electrons which have shorter wavelengths than light
• Advantages of electron microscopes

  Greater magnification and resolution
• Disadvantages of electron microscopes

  Expensive

  Less portable

  Require training to use

  Only dead specimens can be viewed