Microscopy • Biology Lab Review

Vocabulary flashcards covering microscope components, functions, magnification, illumination, and lab procedures from the Biology Lab review.

Ocular lens

The eyepiece you look through; usually magnifies $10\times$.

Objective lenses

Lenses that magnify the specimen at different powers.

Revolving nosepiece

Microscope component that holds the objective lenses and rotates to change magnification.

Stage

Microscope platform that supports the slide or specimen.

Stage clips / mechanical stage

Components that hold the slide in place on the stage.

Stage adjustment knobs

Knobs that move the slide left, right, forward, and backward.

Condenser

Component that concentrates light onto the specimen.

Iris diaphragm

Component that controls the amount of light passing through the specimen.

Illuminator

The light source used to view the specimen.

Coarse-focus knob

Knob that makes large, rapid adjustments to bring a specimen into general focus; used during initial focusing on low power.

Fine-focus knob

Knob that makes small adjustments to sharpen the image.

Arm (microscope)

Supports the upper portion of the microscope; held when carrying the microscope with the other hand under the base.

Base (microscope)

Supports the microscope and often houses the light source.

Scanning objective

The lowest-power objective (usually $4\times$) used first when focusing to provide the widest field of view and make finding the specimen easier.

Total magnification formula

$$\text{Ocular lens magnification} \times \text{objective lens magnification}$$

Total magnification ($4\times$ objective)

Magnification achieved using a $10\times$ ocular and a $4\times$ objective: $10 \times 4 = 40\times$.

Total magnification ($10\times$ objective)

Magnification achieved using a $10\times$ ocular and a $10\times$ objective: $10 \times 10 = 100\times$.

Total magnification ($40\times$ objective)

Magnification achieved using a $10\times$ ocular and a $40\times$ objective: $10 \times 40 = 400\times$.

Total magnification ($100\times$ objective)

Magnification achieved using a $10\times$ ocular and a $100\times$ objective: $10 \times 100 = 1000\times$.

Compound microscope

A microscope that generally has higher magnification, uses transmitted light from below, and produces a 2D image of thin, often transparent specimens mounted on slides.

Stereoscope

A microscope that generally has lower magnification, commonly uses reflected light from above, and produces a 3D appearance of larger, solid specimens.

Transmitted light

Light that passes through the specimen before reaching the observer; commonly used by compound microscopes.

Reflected light

Light that shines onto the specimen and reflects off its surface toward the observer; commonly used by stereoscopes.

Safe focusing steps

Start on low power, center the specimen, use coarse focus to find it, use fine focus to sharpen, switch to higher power, and use fine focus only.

Microscope carrying procedure

Hold the arm with one hand and support the base with the other.