Magnifying 3 letters on a newspaper
- Cut 3 letters from a newspaper. They must look different when laterally inverted or upside down. (e.g. R or e)
- place it on a glass slide and add 2 drops of water. The letters should be soaked with some water left on the slide.
- 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.
- Secure the slide on the stage with the stage clips
- Observe the letters through the microscope starting at 40x magnification.
- 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)
Depth of field
- cut three 1.5cm threads of different colours (blue, black and green)
- Repeat steps 2-5 from Investigation 1
Depth of field –> the range of distance where the object looks sharp
Positions of threads:
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.
- Use a toothpick to scrape the inside of your cheek. Wipe the residue on the glass slide.
- Repeat steps 2-5 from Investigation 1, using iodine instead of water
- 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: