Microscopy and the Compound Microscope

Flashcards covering the terminology, parts, functions, and magnification calculations for the compound bright-field microscope as presented in the lab lecture.

Compound Microscope

A microscope that uses multiple convex lenses to magnify objects, utilizing both ocular and objective lenses to provide a higher degree of magnification than a single lens.

Bright-field Microscope

A microscope where the specimen is illuminated with light and appears as a darker or stained image on a light background.

Parfocal

A design feature meaning that when an object is in focus with one power, it should remain in focus (or very close to it) when switched to another power.

Oculars (Eyepiece)

The lens where the specimen is viewed, typically containing a $10\times$ magnification ocular lens.

Body Tube / Head

The part of the microscope that holds the optical parts and connects the eyepiece to the objective lenses.

Arm

The part that connects the head to the base and supports the microscope; it should be grasped when carrying the instrument.

Coarse Adjustment Knob

The larger knob used to move the stage up and down to adjust focus of the samples, primarily used with the scanning power objective.

Fine Adjustment Knob

The smaller knob used to adjust sharpness or finer details of the samples; it moves the stage slightly to sharpen the image.

Base

The bottom part that supports the microscope and holds the illuminator.

Rheostat

The light adjustment control or light intensity knob located on the base of the microscope.

Mechanical Stage

The platform where the sample/slide is placed for viewing.

Mechanical Stage Knobs

The X-Y knobs used to move the slide horizontally and vertically across the stage.

Condenser

Located under the stage, this part collects and focuses light into the sample.

Iris Diaphragm

A component of the condenser that regulates the amount of light projected onto the specimen.

Illuminator

The substage light source used to illuminate the sample.

Revolving Nosepiece

An inclined, circular metal plate that holds multiple objective lenses and can be rotated to change magnification.

Objective Lenses

Optical lenses that collect light and project magnified samples to the eyepiece, typically ranging from $10\times$ to $40\times$ in magnification.

Scanning Power Objective

The red-ringed objective lens with a magnification of $4\times$.

Low Power Objective

The yellow-ringed objective lens with a magnification of $10\times$.

High Power Objective

The blue-ringed objective lens with a magnification of $40\times$.

Oil Immersion Objective

A white-ringed objective lens with a magnification of $100\times$, though not always present on every microscope.

Total Magnification Formula

$$\text{Total Magnification} = \text{Power of Objective lens} \times \text{Power of the Oculars}$$

Total Magnification Example: High Power

$$\text{High Power } (40\times) \times \text{Oculars } (10\times) = 400\times$$

Lens Paper

The specific non-abrasive paper provided to clean the oculars and objectives of the microscope; normal paper towels are considered too abrasive.

Stage Clips

The components used to hold the slide in place on the stage.