forensics chapter 7 vocab

Arm

a C-shaped upright structure, hinged to the base that supports the microscope and acts as a handle for carrying

Base

the support on which the microscope rests

binocular

describes a microscope with two eyepieces

Body tube

a cylindrical hollow tube on which the objective and eyepiece lenses are mounted at opposite ends and is a corridor through which the light passes from one lens to another

Coarse adjustment

large Knob focuses the microscope lenses on specimens by raising and lowering the body tube

Comparison microscope

two compound microscopes combined into one unit so the viewer looking through the eyepiece lens observers a circular field, equally divided into two parts by a fine line

Condenser

the lens system under the microscope stage that collects light rays from the base illuminator and focuses them onto the specimen

Depth of focus

the thickness of a specimen that is entirely in focus under a microscope

Eyepiece lens

the upper lens of a compound microscope, into which the viewer looks

Field of view

the area of the specimen that can be seen after it is magnified

Fine adjustment

smaller knob that focuses lens at much smaller magnitudes

Illuminator

artificial light supplied by a lightbulb to illuminate the specimen being examined

Microspectrophotometer

an instrument that links a microscope to a spectrophotometer

Monocular

describes a microscope with one eyepiece

Objective lens

the lower lens of a compound microscope; it is positioned directly over the specimen

Parfocal

describes a microscope such that when an image is focused with one objective in position, the other objective can be rotated into place and the field will remain in focus

Plane-polarized light

light confined to a single plane of vibration

Polarizer

a device that permits the passage of light waves vibrating in only one plane

Polarized microscope

is used to study birefringent materials, that have double refraction

Real image

an image that can be seen directly with the naked eye

Scanning electron microscope SEM

bombards a specimen with a beam of electrons instead of light to produce a highly magnified image

Stage

the horizontal plane on which the specimens are placed for study

Stereoscopic microscope

consists of two monocular compound microscopes properly spaced and aligned to present a three-dimensional image to the viewer

Transmitted illumination

Light that passes up from the condenser and through the specimen; it is used to examine transparent specimens

vertical or reflected illumination

Illumination of a specimen from above; it is used to examine opaque specimens

Virtual image

an image that cannot be seen directly, but can be seen only by a viewer looking through a lens