microscopes

• units of measurement

  x 10 x1000 x1000

  cm ⁐ mm ⁐ hm ⁐ nm

  /10 /1000 /1000
• equations

  $actual size=$$imagesize/magnification$

  $magnification =$$image size/actual size$

  $image size =$$magnification *$$actual size$
• total magnication =

  magnifying power of objective lens x magnifying power of eyepiece lens
• characteristics of a microscope

  A) body tube

  B) nosepiece

  C) low power objective

  D) medium power objective

  E) high power objective

  F) stage clips

  G) diaphragm

  H) lamp/mirror

  I) eyepiece

  J) arm

  K) stage

  L) fine focus

  M) coarse focus

  N) base

  
• light microscopes

  • study living cells and for regular use when relatively low magnification and resolution is enough
• electron microscopes

  • provides higher magnifications and higher resolution images but cannot be used to view living cells
• 6 marker answer

  • turn light on
  • put slide on stage
  • use lowest power obj lens
  • bring stage to lens using the coarse focus wheel
  • use fine focus wheel to bring cells into focus
  • use the next objective lens and the coarse focus wheel into view and fine focus to focus cells
• advantages

  electron microscope

  • higher magnification
  • higher resolution

  light microscopes

  • living cells
  • no risks of radiation leaking
• disadvantages

  electron microscopes

  • cant see living cells
  • risks of radiation leaking

  light microscopes

  • lower resolution
  • lower magnication
  • only when presence of light
• why is a thin sample of tissue required?

  allows light to pass through so internal structures can be observed
• why is water added to the slide before the sample is mounted?


  allows the sample to be suspended between the slide and the cover slip, and ensures the cover slip to stay in place
• why is iodine solution added to stain cells?


  it adds contrast as it allows internal structures to become more visible
• why is the cover slip lowered using a mounting needle?


  ensures that no air bubbles are trapped
• what safety precaution should be taken during this experiement?


  wear safety goggles when handling iodine solution