microscope lab

how to handle a microscope

1. Carry a microscope by supporting it in both hands in an upright position. One hand should grasp the microscope arm while the other provides a flat platform for its base. 2. Place it down on a flat surface that has been cleared of debris. 3. If your microscope has a rheostat, which adjusts light intensity, make sure it is turned to minimum light intensity before turning on the light. 4. Clean all lenses by wiping with grit-free lens paper. 5. When you adjust focus, always begin with the lowest power first. Avoid contacting the lens to the microscope slide on the stage.

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?

350X

condenser

A lens located just below the stage, it concentrates light on the specimen. In many microscopes, the condenser includes a knob that raises and lowers it to control light intensity

substage light

A light within the base providing the light source for illumination of the specimen. A switch, usually at the side or front of the base, turns it on and off, and a dial (rheostat) adjusts the light intensity. In some microscopes the substage light is replaced by a mirror, which requires an external light source.

head

Also called the body tube, it is the upper part that contains the viewing pieces (the lenses and rotating nosepiece) includes the ocular lense, nosepiece, objective lenses

After placing a slide onto a microscope to observe a specimen, you should:

Begin at scanning power

nosepiece

Located below the ocular lenses, it serves as an attachment for the objective lenses. The viewer can rotate the nosepiece to change from one objective lens to another.

You may change the contrast of an observed image through the microscope by:

Moving the iris diaphragm lever

When using a compound microscope, you should look through the:

Ocular lens

ocular lenses

The eyepieces, which are two removable lenses that you look through to observe the microscope specimen.

stage

The flat platform connected to the arm and suspended beneath the objective lenses, upon which the microscope slide with its specimen is placed. The stage often includes either a mechanical stage or stage clips, both of which keep the slide stationary during viewing.

Your lab microscope is parfocal. This means that:

The focus doesn't change significantly when the objective lens is changed.

fine adjustment knob

The knob on either side is used for precision focusing, since they raise or lower the stage in very small increments.

arm

The narrow, vertical part connecting the head and base. It may be straight or curved.

base

The supportive bottom piece of the microscope includes the substage light

objective lenses

Three or four objective lenses that are usually attached to the nosepiece, each with a different magnification: usually 4X or scanning, 10X or low power, 40X or high power, and if present, 100X or oil immersion.

When you first begin to work with the microscope, before turning the light on you should always:

Turn the light rheostat to low intensity

coarse adjustment knobs

Two knobs on either side of the base of the arm. They are usually the largest knobs on the arm. Turning them raises and lowers the stage in large increments, bringing it closer to or farther from the objective lens. Thus, these knobs control the focus. You may use either knob or both for the same effect. The coarse adjustment knob should only be used at scanning power (4X) to avoid contacting the objective lens with the microscope slide.

what are the three most common microscopes

compound microscopes, stereomicroscopes, and electron microscopes

You should always begin observation of specimens with the highest power.

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When using a microscope and moving the objective lens from low power to high power, it is important to always:

focus with the fine adjustment knob

iris diaphragm lever

lever located beneath the condenser, it opens and closes the iris diaphragm attached to it.

When preparing a wet mount, you must contact the edge of the coverslip to the liquid containing the specimen, then gently:

lower the coverslip onto the specimen

total magnification

objective lens x ocular lens (10x)

Which part of the microscope does the microscope slide rest on while being viewed?

stage

Resolution

the ability to distinguish between two objects; the greater the resolution, the smaller the distance between them.

field of view

the greater the magnification of a lens, the closer it is to the slide, so the field of view is smaller and the image appears larger.

How do you clean the lenses of your microscope?

with special lens paper and cleaner