Experimnet #1: Microscopy
Microbiology Lab Practical #1
Terms in this set (20)
What are the two lenses present in a compound microscope?
*Ocular lens - located in the eyepiece
*Objective lens - located in the revolving nosepiece
the light source in the base of the microscope
is a two lens system that collects and concentrates light from the illuminator and directs it to the iris diaphragm
regulates the amount of light entering the lens system
Mechanical Stage Control
a platform used to place the slide on which has a hole in the center to let light from the illuminator pass through. Often contains STAGE CLIPS to hold the slide in place.
houses the lens system that magnifies the specimens
*Upper end - Oculars/Eye pieces: what you view through
*Lower end - Nose-piece: revolves and contains the objectives
magnifies the specimen, producing a real image
real image is magnified by the ocular lens, resulting in the final image
can be calculated by multiplying the objective lens value by the ocular lens value
is the ability of a lens to show two adjacent objects as discrete entities.
is dependent on the REFRACTIVE INDEX or the bending power of light
has the same refractive index as glass, diminishes the loss of refracted light and improves resolution
is the ability to distinguish an object from its background
is the "thickness" of the sample that appears in focus at a particular magnification
as the magnification increases the depth-of-focus decreases, or the "slice" of the sample appears in focus gets thinner
means that if one objective lens has the object in focus, and you go to the next objective lens, only minor adjustment (fine focus) is needed to bring the image back into focus
is the area of the slide that you are observing through the microscope
refers to the ability to keep an object in the middle of your field-of-view when changing from one objective to another
is a two lens system that collects and concentrates light from the illuminator and directs it to the Iris Diaphragm
Fine - Adjustment Knob
once object is in view and you go higher in magnification, you use this knob to put objects into focus
Coarse - Adjustment Knob
to use at lower magnifications to bring sample into view
What is the purpose of adding immersion oil when using the 100X objective?
*air has a lower refractive index than glass, light waves have a tendency to bend and scatter as they pass through the air from the glass slide of the objective lens.
*the immersion oil takes away the "air" space between the slide and the objective to not refract the light