Microscopes

• An electron microscope has much higher magnification and resolving power than a light microscope
• Electron microscopes can be used to study cells in much finer detail which has enabled biologists to see and understand many more sub-cellular structures
• Light microscopes use light and lenses to form an image of a specimen and magnify it
• Light microscopes allow us to see individual cells and large subcellular structures like nuclei
• Electron microscopes use electrons to form an image and have a higher resolution than light microscopes
• Electron microscopes let us see the internal structure of some subcellular structures
• $Magnification=$$\frac{size\;of\;image}{size\;of\;real\;object}$
• • A: Eyepiece
  • AB: Stage
  • AC: Condenser/Diaphragm
  • B: High and low power objective lenses
  • C: Coarse focus adjustment
  • D: Fine focus adjustment
  • E: Light 


  Light microscope

  
• The condenser on a light microscope focuses light on the specimen
• The diaphragm on a light microscope controls the amount of light to the specimen
• Light microscope practical

  • Cut up an onion and use tweezers to peel off a layer of epidermal tissue
  • Add a drop of water to a clean slide with a drop of iodine to stain and highlight objects in a cell
  • Place the onion in the solution and then place a cover slip making sure that there are no air bubbles
  • Clip the slide onto the stage and use the fine and coarse focus to focus the image