Virtual Microscope Lab

Objectives:

  • Identify the following microscope parts:
  • Coarse adjustment knob
  • Fine adjustment knob
  • Stage
  • Ocular lens
  • Objective lens
  • Label cells that are under a microscope

Part 1. Parts of the Compound Microscope

Ocular lens  – Lens through which you view the magnified specimen. Pointer may appear as a wedge or as a curved line. Micrometer looks like a small ruler.

Objective lens – Lens on the revolving nosepiece that accomplishes the initial magnification of the specimen.

Stage – Flat work surface upon which the slide is placed. Most microscopes have a mechanical stage which is used for precise movement of a slide via control knobs that move the stage.

Coarse adjustment knob – Gives gross movement for initial focus.

Fine adjustment knob – Gives refined movement for finishing focus.

Magnification

The compound microscope combines the magnifying power of the ocular lens with the magnifying power of the objective lens. The magnifying power of each lens is marked on its tubular housing. To obtain the magnification of the microscope, multiply the magnification of the ocular lens times the magnification of the objective lens. For example, if your ocular lens magnification is 10 power, and the lowest power objective is 4 power, then the total magnification is 10 X 4 = 40x.

Go to the Virtual Microscope Website:

https://www.ncbionetwork.org/iet/microscope/

Answer the following questions –and make the drawings.

Make the drawings on a separate page and turn in a screenshot or photo of the drawings.

2Microscope Lab

FIRST CLICK ON “LEARN.”

Click on 5 parts of the microscope. List those parts here and describe (briefly!) what they do.

1.

2.

3.

4.

5.

THEN CLICK ON “EXPLORE.”

When looking at these cells under the “microscope” you will need to use the coarse focus (to locate specimens), fine focus (for getting slightly better focus / detail), and the light adjustment. Also, you can only increase 1 magnification at a time –so you can go from 4x to 10x, but not from 4x to 100x.

Click on the ? and choose the slide that says “Letter E.” Use the coarse focus to get the letter “e” into focus. Then use the fine focus to get it even more in focus.

Questions

  1. What happens to the letter “e” as you go from 4x to 10x to 40 x?
  2. In which magnification can you see the most of the letter “e”?

Click on the plant slides and choose the “plant cells.”

Questions

  1. What structures are visible in this slide?
  2. DRAW 2 or 3 of these cells .

Click on the bacteria slides and choose the gram stain slide. Bacteria are gram stained to differentiate between gram +  and gram – .

Look at the bacteria under 40x or 100 x (although here you will need to click on the immersion oil and add that to the slide.

  1. What type of bacteria do you see ?

3Click on the animal slides and choose the “spider.”

  1. What magnification is the best for drawing most of the spider?
  2. DRAW what you see at this magnification .

Click on the human slides and choose the “blood.” Most of the cells in the view are red blood cells  but there are a few larger white blood cells.

  1. DRAW at 40x

Click on plant cells and then “onion root.”

  1. If you view the cells at 40x, how many cells (roughly what %) are in one of the phases of mitosis?

Find cells that are in anaphase.

  1. DRAW this one cell. Include the plant plasma membrane (and cell wall).

Find cells that are in prophase.

  1. DRAW this one cell. Include the plant plasma membrane (and cell wall).

General Questions

  1. Name all the organelles that were visible in the cells you viewed today.
  2. What are some organelles that were NOT visible in these cells?
  3. What is the benefit of looking at things under the microscope?