practical (onion cell)

• How do you prepare a slide to view an onion cell?

  1. add a drop of water to the middle of a clean slide
  2. Cut up an onion and separate into layers, use tweezers to peel off some epidermal tissue from the bottom of one layer
  3. using tweezers, place epidermal tissue into water on the slide
  4. add drop of iodine solution
  5. place a cover slip on top
• How do you use a light microscope?

  1. Clip the slide you've prepared onto the stage
  2. select the lowest-powered objective lens (one that produces lowest magnification)
  3. Use the coarse adjustment knob to move the stage up to just below the objective lens
  4. Look down the eyepiece. Use the coarse adjustment knob to move the stage downwards until the image is roughly in focus
  5. Adjust the focus with the fine adjustment knob, until you get a clear image of what's on the slide
  6. If you need to see the slide with greater magnification, swap to a higher-powered objective lens and refocus