Microscopy

• What is the definition of magnification ?

  How many times larger the image appears, compared to the real object.
• What is the role of microscope?


  Magnification, magnifies small objects so that they appear larger
• Define resolution


  The smallest distance between two objects that can be distinguished

  Basically how much detail you can see in the image.
• How does a light microscope work?


  Light from a mirror passes through the specimen, objective lens, the eyepiece lens and into your eye.

  The two lenses magnify the image and cause the image to be much larger than the real object.
• What part of the microscope is highlighter above?

  Eyepiece lens
• What are two types of microscopes?


  Light microscope and electron microscope
• What is the magnifying power of a light microscope?


  magnification: x2000
• give 5 advantages of light microscopes compared to electrons microscopes.


  1. Cheap
  2. Easy to use
  3. Small, so easy to transport
  4. Produce colour images
  5. Can see living specimens (e.g. live cells)
• Main disadvantage of light microscopes


  Light microscopes only rely on light whereas electron microscopes rely on electrons.
• What is the magnifying power of an electron microscope?


  magnification: x2,000,000
• What is the main advantage of electron microscope?


  They have greater resolutions and magnification
• Why do electron microscopes have a greater magnification and resolution than light microscopes?


  They use a beam of electrons rather than light waves and electrons have a shorter wavelength than light waves.
• Give 5 disadvantages of electron microscopes


  1. Expensive
  2. Difficult to use
  3. Large, difficult to transport
  4. Images generated in black and white
  5. can only view dead specimens
• μm, m, mm, km, nm, cm - put them in order smallest to largest


  nm

  μm

  mm

  cm

  m

  km
• convert 1mm to m.


  1x10^-3 m
• convert 1μm to m. 


  1x10^-6 m
• convert 1nm to m.

  1x10^-9 m
• how many mm are there in 1cm?


  there are 10mm in 1cm
• how many nm are there in 1μm?


  there are 1000nm in 1 μm
• convert 20mm to μm


  20mm is 20,000μm
• convert 340nm to μm


  340nm is 0.34μm
• convert 2.4cm to mm


  2.4cm is 24mm
• What is the equation for magnification?


  magnification = image size / object size
• rearrange the magnification equation to make object size the subject


  object size = image size / magnification
• Rearrange the magnification equation to make image size the subject


  image size = object size x magnification