I am going to be preparing a slide of an onion piece and looking at it through a microscope in low and high powers. By doing this I expect to accomplish a drawing of an onion cell close up and how to use the assured tools similar to the microscope.

Safety Points:

• Take care not to cut yourself while cutting the onion.
• Make certain with the function of the microscope is handled with care.

• Pay attention not to stain yourself while undertaking the experimentation.

Materials:

• Knife
• Onion
• Dissection scissors
• Fine forceps
• Water
• Pipette
• Microscope slide
• Microscope
• Cover-slip
• Mounted needle
• Iodine solution
• Filter paper

Method:

• I sliced vertically through an onion bulb and detached one of the leaves of the bulb.

• With a pair off of fine forceps I cautiously peeled off its epidermis, being cautious not to separate the cells from the layer beneath.

• Using a razor-sharp pair of dissection scissors I cut out a piece of epidermis about 5mm by 5mm.

• Using a pipette I carefully placed a drop of water on a clean microscope slide.

• I carefully placed the epidermis in the drop of water ensuring that it was flat, using a mounted needle if necessary.

• I positioned a cover slip on top of the epidermis, again making sure that it was kept flat.

• On one side of the cover slip I placed a drop of iodine solution, which was a suitable stain for the plant cells.

• I placed the cut edge of a piece of filter paper to the other side of the cover slip which would draw a small amount of stain beneath the cover slip.

• Viewing with a microscope I looked at the slide through low power then followed by high.

Evaluation:

I could see less detail in the lower magnification and in the high magnification I could see more detail such as the cytoplasm. The lower magnification allowed me to see the nucleus, cytoplasm and cell wall. I could see dozens of cells in low magnification but in high I could see three or four cells at a very close range. One problem which I encountered was that I couldn’t peel the epidermis to a thin tissue. To overcome this I asked my teacher to help me peel it properly. This technique is good because it allows you to look at cells by cutting a small tissue of something. If the water had different chemicals in it then it would have effected the slide because it would show different chemicals when you look at it. If I had more time then I would look at it in different magnifications and would be able to get more accurate readings and drawings.

Results:

Discussion of Vocational Implications:

Two differences between school microscopy and microscopy in the industry is that in school we use light microscopes that need light to obtain the image by reflecting off the mirror and have. In industry however scientists use electron microscopes. Another difference is that scientists have microscopes with more magnifications so they can look deeper into the cell. In school the microscopes used have not got the ability to magnify over 40x (10x4=400). One similarity is that the same method is used. We put the tissue to be examined on the slide and examine it looking through different magnifications. Another similarity is that scientists look at the same things we do in school such as onion slides and other tissues.