1. Microscope Lab
Determining size and diagramming specimens using a compound light microscope

2. Determining size
First turn on the microscope and make sure the lowest objective is in use (4x)
Remember total magnification is the objective lens x the ocular lens
Place the ruler on to the slide table/platform.
Look into the field of view and adjust the ruler so that a mm line is on the edge of the view then measure the field of view in mm. You may have to estimate if a whole mm is not in view.
Convert this measurement into µm.
1 µm=1/1000 mm
Repeat the step for the medium power objective, but NOT HIGH POWER.

3. Determining Size To determine size for high power:
Complete the following equation using low and medium power objectives:
Estimated field diameter x total magnification = a constant
Take the average of your two constants
Now use this constant and the total magnification under high power to determine the size of your field diameter under high power

4. Microscope Lab You will look at the following slides:
Green algae - Chlorella
Generalized Animal Cell
Generalized Plant Cell
3 types of Bacteria (draw all 3)
Paramecium

5. Microscope Lab For each specimen:
Draw and label the specimen at medium
or high power magnification. (Use your
personal judgment as to which is best.) Make sure
that the total magnification is indicated for each
drawing.
Estimate the size of the cell using any of the objectives. Indicate how the size was determined for each one.
Each of these must be completed individually even if you are sharing a microscope.

6. When using outside sources, please include bibliographic information
Homework Questions
Why is it important to know the size of specimens under the microscope?
Explain the importance of surface area and volume with regard to cell size.
Evolutionarily, why are limits placed on cell size?
Find the average size for the following life forms and place them in order from smallest to largest: paramecium, common cold virus, e.coli bacteria, cholera bacteria. Explain your reasoning for the order.
For the paramecium and chlorella: Give a brief description of the life form. Where might the cell be found? How does it live? Any interesting facts about the life form?
When using outside sources, please include bibliographic information