Light Microscopy – Parts of a Binocular Compound Microscope

Vocabulary flashcards summarizing the structure names and functions of components on a typical binocular compound light microscope.

Ocular lenses (eyepieces)

Pair of lenses you look through; usually 10× (sometimes 15×) magnification and often contain a pointer.

Head

Upper portion holding the ocular lenses and the rotating nosepiece.

Arm

Vertical support connecting head and base; serves as a carrying handle.

Rotating nosepiece

Revolving mount for objective lenses; turned to select different magnifications.

Scanning objective lens

4× magnification; shortest objective, used to scan the entire slide.

Low-power objective lens

10× magnification; longer than scanning lens, provides greater detail.

High-power objective lens

40× magnification; offers still greater detail of the specimen.

Oil-immersion objective lens

100× magnification; used with immersion oil for the greatest magnification.

Mechanical stage / Stage clip

Device that secures the specimen slide in place on the stage.

Mechanical stage control knobs

Two knobs that move the slide horizontally and vertically while viewing.

Stage

Flat platform beneath objectives where the specimen slide is placed.

Condenser

Lens below the stage that concentrates light on the specimen; closer position narrows and intensifies the beam.

Condenser control knob

Adjusts the height/position of the condenser.

Iris diaphragm lever

Opens or closes the diaphragm to regulate light passing through the condenser.

Coarse adjustment knob

Large knobs that rapidly raise or lower the stage for initial focus; use only with 4× or 10× objectives.

Fine adjustment knob

Smaller knobs for precise focusing; safe with 40× and 100× objectives.

Substage light

Built-in lamp in the base providing illumination for the specimen.

Rheostat

Dial that controls the intensity of light from the substage lamp.

Base

Bottom support of the microscope that rests on the work surface.