Module 2 - Virtual Microscopy Activity

Limitations of the compound light microscope are

Properties of light limit the resolving power. They cannot resolve detail finer than about 0.2 micrometers and do not magnify beyond 1500 times the true size of the specimen. Because light microscopes are limited in resolve and magnification, biologists were not able to study the small details and complex structures inside cells until the development of electron microscopes.

the TEM works by

TEM's pass a beam of electrons through a thin specimen to form a magnified image

The dissecting microscope is most useful for viewing

The dissecting microscope is used for examining organisms or objects at relatively low magnifications (organs and tissue)

The compound light microscope works by

the light source is below the stage, and the light shines up through the magnification lenses. You can prepare the specimen for viewing by placing it on a rectangular glass slide. It can be stained with a dye that adds contrast to nearly transparent cells.

Limiations of the TEM is

the specimen must be sliced very thin, thus making the preparation more difficult to use.

describe the detail that can be seen under the SEM microscope

you can see a very detailed image of the object's three-dimensional surface

limitations of the SEM are

you have to coat the specimen in a thin layer of gold or metal so that the electrons bounce off of its surface

The compound light microscope is most useful for viewing

A compound light microscope is an instrument that uses visible light and magnifying lenses to examine small objects that are not visible to the naked eye, or in finer detail than the naked eye allows. (tissue samples, blood, microorganisms in a pond, microscopic cells, and some of the larger details within the cells.)

Describe the detail that can be seen under the compound light microscope

Compound light microscopes can be used to view tissue samples, blood, microorganisms in pond water, microscopic cells, and some of the larger details within the cells.

Limitations of the dissecting microscope are

If you need high magnification, this is not the microscope for you to use

the SEM microscope works by

The electron beam scans the specimen in a thin layer of gold metal. The electrons that scatter off the gold-coated surface are focused onto a screen, forming a detailed image of the specimen surface.

Describe in detail that can be seen under the dissecting microscope

You can use it to view the surfaces and details of leaves, stems, mold, spores, or other small objects that can be seen with the naked eye but require magnification in order to be examined closely.

The dissecting microscope works by

a beam of light is produced above the stage and reflects off of the specimen's surface, passing through the glass lenses that magnify the image.

the SEM is most useful for viewing

can be used to see specimen in great detail - mainly used for studying the internal structures of cells that cannot be viewed under light microscopes

the TEM is most useful for viewing

can be used to see the internal structure of cells.

Describe the detail that can be seen in the TEM

detailed black and white "shawdow" image of the specimen, with its different structures displayed in varied darkness according to their density.