Exercise 3: The Microscope

Stage

Platform the slide rests on while being viewed -has a hole to permit light to pass through the stage and through the specimen

Iris Diaphragm Lever

Shutter with the condenser that can be controlled by a lever to adjust the amount of light passing through the condenser.

Condenser

Small non magnifying lens located beneath the stage that concentrates the light on specimen. The condenser may have a knob that raises and lowers the condenser to bury the light delivery. Generally, the best position is close to the inferior surface of the stage

Base

The bottom of the microscope. Provides a sturdy flat surface to support and steady the microscope

Stage

The microscope slide rests on the ______________ while being viewed.

Real image

The objective lens magnifies the specimen to produce a ____ that is projected to the ocular

Objective lenses

These ones are attached to the nose piece. Usually a compound microscope has four lenses: scanning (for Alex), low - power (10 X), high - power (40 X), and oil immersion (100 X) lenses. Typical magnifying powers for the objectives are listed in parentheses

Coarse adjustment knob

This knob allows you to make large adjustments to the height of the stage to initially focus your specimen

Fine adjustment knob

This knob is used for precise focusing once the initial coarse focusing has been completed

Virtual image

This real image is magnified by the ocular lens to produce the ____ that your eye sees

False

True or False? You should always begin observation of specimens with the oil immersion lens

The slide should be almost in focus when changing to higher magnifications

Your lab microscope is Parfocal. What does this mean?

Storage rules

before putting microscope away, -remove slide from stage -rotate lowest-power objective lens into position -wrap cord neatly around base -drop stage halfway -replace dust cover

Lowest power objective lens

begin focusing process with this objective power lens in position

350X

if the ocular lens magnifies a specimen 10x, and the objective lens used magnifies the specimen 35x, what is the total magnification being used to observe the specimen?

Lowest power lens

only use coarse adjustment knob with these lens

Special grit-free lens paper

paper used to clean lenses

Nosepiece

rotating mechanism at base of the head -carries three or four objective lenses over light beam passing through hole in stage

Coverslip

should always be used with wet mount preparations

Head or body tube

supports objective lens systems -mounted on a movable nosepiece & ocular lens lenses

Depth of Field

the thickness of the plane that is clearly in focus

Arm

vertical portion of microscope connecting base and head

Compound Microscope

A precison instrument and should always be handled with care

Resolution (or resolving power)

Although the level of magnification is almost limitless, ____ that is, the ability to discriminate two close objects as separate, is not

Ocular lenses

Binocular microscope's will have two lenses located in the eyepieces at the Sapir your end of the head. Most ocular lenses have a magnification power of 10 X. Some microscopes will have a pointer and / or reticule (micrometer), which can be positioned by rotating the ocular lens

Resolving Power

Determined by the amount and physical properties of the visible light that enters the microscope

Total Magnification (TM)

Equal to the power of the ocular lens multiplied by the power of the objective lens used

Proper technique for transporting microscope

Hold it in an upright position with one hand on its arm and the other supporting its base -Avoid swinging and jarring instrument

Mechanical stage

Holds the slide in position for viewing -has two adjustable knobs that control precise movement of the slide

With special lens paper and cleaner

How do you clean the lenses of your microscope?

Substage light or mirror

Located in the base. The light from the lamp passes directly upward through the microscope.

Light control knob

Located on the base or arm. This stage allows you to adjust the intensity of the light passing through the specimen