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

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.

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

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

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.

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