microscropy

• a slide is a strip of clear glass or plastic onto which the specimen is mounted
• 1. add a drop of water to the middle of a clean slide
  2. cut up onion and separate layers. Use tweezers to peel of some epidermal tissue from the bottom of one of the layers.
  3. place epidermal tissue into water (with tweezers)
  4. add a drop of iodine solution.
  5. place a cover slip on top. stand the cover slip upright on the slide next to the droplet. then carefully tilt and lower (air bubble obstruct view of specimen)
• 1. clip the slide youve prepared onto stage
  2. select the lowest powered objective lens
  3. use the coarse adjustment knob to move the stage up to just below the objective lens
  4. look down the eyepeice. 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 whats on the slide
  6. if you need to see the slide with greater magnification swap to a high powered objective lens and refocus
• iodine solution is a stain. stains are used to highlight objects in a cell by adding colour to them
• a cover slip is a square of thin, transparent plastic or glass
• microscopes let us see things that we cant see with the naked eye
• light microscopes use light and lenses to form an image of a specimen and magnify it. they let us see individual cells and large subcellular structures like nuclei
• electron microscopes use electrons instead of light to form an image. they have a much higher magnification than light microscopes
• electron microscopes also have a higher resolution. they let us see internal structure of mitochondria and chloroplasts. they even let us see tinier things like ribosomes and plasmids
• resolution is the ability to distinguish between two points so a higher resolution gives a sharper image size
• magnification= image size/real size