Microscopy

• what is the equation of magnification

  Magnification = size of image/size of real object
• how do you prepare a specimen slide

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

  2. use tweezers to place the specimen on the slide

  3. use the forceps to ensure it is flat

  4. add 2 drops of iodine

  5. place a cover slip on top lowering it with a mounted needle
• how do you prevent air bubbles forming under the cover slip

  by lowering it at an angle
• How to use a light microscope

  1. Clip the slide to you've prepared onto the stage

  2. Select the lowest-powered objective lense

  3. use the coarse adjustment knob to move the stage up to just below

  4. Look down the eyepiece and turn the coarse adjustment knob
• rules for biological drawrings

  -always use pencil

  -label lines must be drawn horizontal with a ruler

  -no sketched lines

  -must have a title
• light microscopes


  uses mirrors and light to form images

  lower magnification than electron microscopes

  lower resolution than electron microscopes
• advantages of light microscopes

  relatively cheap, easy to use, enables us to see individual cells. Specimen can be living
• disadvantages of light microscope

  Can't see small organelles like ribosomes
• electron microscope


  -uses beams of electrons to form images

  -higher magnification then light microscopes

  -higher resolution than light microscope
• advantages of electron microscopes

  able to see small structers and produce a clearer image
• disadvantages of electron microscope

  expensive

  need specialist training

  specimens can't be living