Sarah Pham (slp2723)
Section #48955
BIO 206L: Exercise 3 Lab Report
1.
a) The oculars are located at the top of the microscope above the objective lenses. Oculars
function as eyepieces which produces a magnified virtual image of the real image.
b) The objective lenses are located above the stage and below the oculars. Objective lenses
function in collecting the light after it passes through the object to produce a magnified real
image.
c) The stage is located right below the objective lenses and above the condenser. The stage
functions as a moveable platform that moves the specimen closer or further from the objective
lenses.
d) The condenser is located beneath the stage and contains lenses which shape the direction of
the light before it encounters the object.
2. Limitations to clearly viewing living cells using light microscopy is that with a light
microscope you can only view objects that are as small as the shortest wavelength of visible
light; any microorganism that is smaller than that cannot be seen by the light microscope. The
maximum resolution of a light microscope is 250nm which means that you cannot distinguish
two objects that are closer than 250nm apart. Moreover, microscopic objects have no contrast
under a light microscope which means that most specimens are completely transparent. In
order to see contrast in the specimen, dyes such as stains are used. However, most stains tend
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- Spring '08
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- objective lenses
