Microscope investigations

Investigation 1:

Magnifying 3 letters on a newspaper

Steps:

  1. Cut 3 letters from a newspaper. They must look different when laterally inverted or upside down. (e.g. R or e)
  2. place it on a glass slide and add 2 drops of water. The letters should be soaked with some water left on the slide.
  3. place one side of the cover slip on the water. slowly lower the cover slip, using a pen to support it. when it is almost flat against the slide, slide the pen out.
  4. Secure the slide on the stage with the stage clips
  5. Observe the letters through the microscope starting at 40x magnification.

Observations:

  • The letters are upside down and laterally inverted (drawing: http://www.scriblink.com/index.jsp?act=phome&ld=1&rid=600&cid=808)
  • When the slide is moved to the right, the image in the eyepiece moves to the left and vice versa
  • I had to turn the adjustment knobs towards me to focus the letters.
  • When I switched to high power magnification, the field of view was smaller
  • I had to center the letters before I switched to high power magnification. If not, I would lose sight of the letters.
  • The position of the image did not change
  • There was a dark line across my field of view (the pointer)

Investigation 2:

Depth of field

Steps:

  1. cut three 1.5cm threads of different colours (blue, black and green)
  2. Repeat steps 2-5 from Investigation 1

Depth of field –> the range of distance where the object looks sharp

Positions of threads:

http://www.scriblink.com/index.jsp?act=phome&ld=1&rid=582&cid=783

Observation:

When I turned the fine adjustment knob, the thread on the first layer (i.e the blue thread) came into focus first, followed by the one on the second layer and so on.

Investigation 3:

Cheek cells

Steps:

  1. Use a toothpick to scrape the inside of your cheek. Wipe the residue on the glass slide.
  2. Repeat steps 2-5 from Investigation 1, using iodine instead of water

Observations:

  • The cheek cells were thin, like paper. Most were clustered on top of each other.
  • The cells had a very simple structure. (nucleus, cytoplasm, cell membrane and organelles)
  • They were stained brown by the iodine
  • Grey specks were floating around the cells

Diagram of cells:

http://www.scriblink.com/index.jsp?act=phome&ld=1&rid=591&cid=796

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