The Petrographic Microscope Flashcards
polarizing microscope is
PETROGRAPHIC MICROSCOPE
a type of microscope used to identify rocks and minerals in thin section and to investigate microscopic textures and features that are present in minerals and rocks
PETROGRAPHIC MICROSCOPE
accommodates the lamphouse, which contains a 50-100W high-energy tungsten-halogen lamp, and sometimes a transformer and a potentiometer
BASE
a steady light source (often halogen) used for transmitted light microscopy
ILLUMINATOR
used to turn the illuminator on
SWITCH
trades voltage for current in a circuit, while not affecting the total electrical power
TRANSFORMER
used to measure displacement in any direction
POTENTIOMETER
dynamically adjust the LED brightness to suit changing ambient illumination levels or brightness
ILLUMINATION INTENSITY
added to compensate for the odd color of the light, providing a truer white light to pass through the sample
FILTER
parts of the microscope that are located above the base but below the stage
SUBSTAGE ASSEMBLY
cuts down the amount of light that reaches the sample by restricting the area that light can pass through
DIAPHRAGM
other name for diaphragm
APERTURE
consists of two or more lenses that focus the illuminator light onto the sample placed on the stage
CONDENSER
an optical filter BELOW the stage that lets light waves of a specific direction pass through while blocking light waves of other directions
LOWER POLARIZER
platform upon which the thin section is placed
STAGE
has degrees marked on it: 360° around the circular stage, in units of 1 degree
GONIOMETER/VERNIER SCALE
an accessory which can be attached to the top of the rotating stage
MECHANICAL STAGE
can be used to hold the slide in place if no mechanical stage is present
CLIP
knobs on each side
of the microscope
FOCUS
used to rapidly change the level of the stage and sample
COARSE FOCUS
used to gently bring a sample into complete focus
FINE FOCUS
main magnification mechanism in the microscope
OBJECTIVES
where the objectives are mounted
REVOLVING NOSEPIECE
an optical filter ABOVE the stage that lets light waves of a specific direction pass through while blocking light waves of other directions
UPPER POLARIZER
what is an upper polarizer also called
ANALYZER
changes the plane of focus so that the viewer can observe interference figures
AMICI-BERTRAND LENS
directs where the polarized light goes
TUBES
used to observe the sample, often 10x magnification and has one with crosshairs with a distance scale.
EYEPIECES
what are eyepieces also called
OCULARS
which ocular will typically include crosshairs with a distance scale in micrometers
RIGHT OCULAR
COMMON ISSUES
basahin mo na lang baks
thick slice of rock attached to a glass slide with epoxy
THIN SECTION
supposed thickness of a thin section
30 micrometers or 0.03 mm
layers of a prepared thin section from down up
- glass slide
- epoxy
- rock sample 30 µm
- epoxy
- cover slip
t or f
the larger the grit number, the finer the abrasive sand
T
magnification of the eyepiece is 10×, magnification of the objective is 2.5×. what is the total magnification of the microscope?
25X
which of the following parts of the microscope is normally part of the substage?
transformer
analyzer
goniometer
lower polarizer
LOWER POLARIZER
its function is used to view the thin section
OCULAR
its function is the source of light
ILLUMINATOR
its function is to control the amount of light
APERTURE
this is where objectives are mounted
NOSEPIECE
t or f
vibration direction of light after it passes the polarizer is parallel to the analyzer
F
the epoxy/balsam used to mount the thin section should have a similar refractive index as
GLASS
