microscopy

• magnification - tells the size of an image seen through a microscope is compare to the real object
• resolution - ability to distinguish between two or more objects that are close together
• light microscope

  • light passes through the specimen
  • better resolution than the human eye
  • low, medium and high magnification settings
  • allowed for plant and animal cells to be seen as seperate objects with a resolution of 0.25 micrometers
• electron microscopes

  • electrons are passed through the specimen
  • resolve distance of 0.25 micrometers with magnification of x500,000
  • allowed scientists to see sub-cellular structures
  • allowed scientists to study how structures function using black+white images called electron micrographs
• 1km = 1 kilometer = 1000m

  1cm = 1 centimeter = 0.01m

  1mm = 1 millimeter = 0.001m

  1μm = 1 micrometer = 0.000001m

  1nm = 1 nanometer = 0.000000001m
• prefixes like kilo, centi, milli, micro, nano show the magnitude (size) of the value
• Microscope

  • Used to see cells and other tiny specimens
  • Light microscopes can magnify up to 2000 times
  • Electron microscopes can magnify up to 2 million times
• how to use it:

  1. put a thin sample onto a microscope slide
  2. add a few drops of a suitable dye/stain to your sample
  3. place a coverslip on top of the sample and place onto the stage
  4. use the obejective lens with the lowest magnification and focus on the sample
  5. increase the magnification and refocus to see the different features
• to work out the total magnification

  magnification of objective lens x magnification of eyepiece lens
• magnification

  image size / actual size
• image size = actual size x magnification
• actual size = image size / magnification
• microscopes have:

  • eye peice
  • objective lens
  • stage
  • mirror / light source
  • arm
  • fine focus
  • coarse wheel