microscopy

• Microscopy


  The study of things that can only be seen with a microscope
• Cells are studied using microscopes
• Light microscopes


  • Use light and lenses to form an image of specimens
  • Have a lower magnification than electron microscopes
• Electron microscopes


  • Use a beam of electrons to form an image
  • Have a much higher magnification than light microscopes
  • Have a higher resolution than light microscopes
• Electron microscopes allow us to see things in the details of mitochondria and chloroplasts
• Calculating magnification


  1. Image size / Real size

  2. Convert units
• It's a very well known formula to calculate magnification
• Preparing a slide for microscopy

  1. Add a drop of water to the middle of a clean slide

  2. Cut up an onion and place epidermal layer in the water

  3. Add a drop of stain solution

  4. Place cover slip on top
• Using a light microscope

  1. Clip slide onto stage

  2. Select lowest powered objective lens

  3. Use coarse adjustment to bring slide close to lens

  4. Look through eyepiece and use fine adjustment to focus

  5. Swap to higher powered lens to increase magnification
• Drawing microscope observations


  • Use pencil with sharp point
  • Drawing should take up at least half the space
  • No colouring or shading
  • Draw subcellular structures in proportion
  • Include title, magnification, and label key features
• You can work out the real size of a cell by counting the number of cells along 1 mm and using the magnification formula
• A light microscope is better than a heavy one