microscopy

• What do microscopes allow us to do?

  see things that we can’t see with the human eye
• what does light microscopes use?

  light and lenses to form an image of specimen and magnify it (make it look bigger)
• what do light microscopes allow us to do?

  lets us see individual cells and large sub-cellular structures like nuclei
• What do electron microscopes use to form an image?

  electrons
• what do electron microscopes allow us to do?

  lets us see smaller things in more detail example- internal structure of mitochondria and chloroplasts
• Example of a specimen - this is to help me understand

  Plant or animal cells
• What is the formula for magnification?

  Magnification = Image height / Object height

  
• What is the conversion for mm to ym to nm?

  N

  
• Standard form

  • first number needs to be between 1 and 10
  • positive indicie = decimal moved left
  • negative indicie = decimal moved right
• What is a slide

  a slide is a strip of clear glass or plastic onto which the specimen is mounted
• describe the practical of preparing a slide to view onion cells

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

  2 - separate the onion into layers and use tweezers to peel of some epidermal tissue from the bottom of a layer

  3 - place the epidermal tissue into the water on the slide

  4 - add a drop of iodine solution - iodine is a stain = stains highlight objects in a cell by adding colour

  5 - carefully place a coverslip on top of the specimen covering it, try not to get any air bubbles under there as they will obstruct your view of the specimen
• what are the parts of a light microscope?

  eye piece, high and low power objective lenses, stage, light, fine adjustment knob, coarse adjustment knob
• What is the first step in using a light microscope? (first step)

  Clip the slide onto the stage
• Which objective lens should you select first when using a light microscope? (second step)

  The lowest-powered objective lens
• Why do you use the coarse adjustment knob initially? (3 step)

  To move the stage close to the lens
• What should you do after moving the stage up with the coarse adjustment knob? (4 step)

  Look down the eyepiece and use the coarse adjustment knob to move the stage downwards until the image is roughly in focus
• How do you achieve a clear image of the slide? (5 step)

  Use the fine adjustment knob to focus
• What should you do if you need greater magnification? (6 step)

  Swap to a higher powered objective lens
• Compare light and electron microscopes

  Electrons have a much higher magnification and Higher resolution then light microscopes
• What do we mean by higher resolution?

  Sharper image
• What does higher magnification mean?

  Making something look bigger
• what are the parts of a microscope?

  eyepiece, High power objective lens, low objective lens, slide, stage, coarse adjusting knob, fine adjusting knob, light