Download MICROSCOPES SLIDE SHOW NOTES

MICROSCOPES SLIDE SHOW NOTES
What is a Microscope?
• An optical instrument used for producing a magnified image of a small object.
Did You Know . . . ?
• The microscope is the most important tool for biologists.
• The first cells were seen in 1663.
The Beginnings
• Of the five senses, the most important is sight.
– The process of gathering information about the environment that we are a
part of.
– The amount of detail that it can provide is severely limited.
• In order to overcome those limitations, humans started to develop instruments like
the magnifying glass, the spectacles, the telescope and the microscope.
Founding Fathers of Microscopy
• Credit for the first microscope is usually given to Zacharias Janssen around the year
1595.
• The first compound microscopes produced by the Janssen’s were simply a tube
with lenses at each end.
• Hooke’s remarkable engineering abilities enabled him to invent and improve many
mechanical devices, including timepieces and the Gregorian telescope.
• In 1665, he coined the word cell to describe the features of plant tissue (cork
from bark of an oak tree).
• Leeuwenhoek made simple (one lens) microscopes.
• He was the first person to describe bacteria (from teeth scrapings) and
protozoan (from pond water).
Compound Light Microscope
• Compound
– Deals with the microscope having more than one lens.
• Light
– The method by which light transmits the image to your eye.
• Microscope
– “Micro” = small
– “Scope” = view
Terminology
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Objective - Lens closest to the specimen.
Ocular - Lens you look through.
Total magnification - The total power of the microscope.
Resolution - The amount of detail you can see in an image.
Focal Point - The point at which the light from a lens comes together.
How Does it Work?
• Microscopes take an image of something generally too small to see with the naked
eye and magnify that image so that the observer can see it in greater detail.
• To magnify images, a microscope uses several lenses to change the angle at which
rays of light strike the eye of the observer.
Microscope Care & Handling
• Transporting - Grab the arm with one hand and place your other hand on the
bottom of the base.
• Handling - Never touch the lens with your fingers.
• Cleaning - Only use lens paper to clean the glass.
• Storage - Put the low power objective in place and the stage all the way up.
Using the Microscope - Before You Start
• Place the microscope on a table with the arm towards you about a fist’s length from
the edge of the table.
• The microscope should be on the lowest power objective and the stage should be all
the way up.
• The diaphragm should be set on the brightest field of view.
- First Focusing
• Place a slide on the stage centering the specimen over the stage opening.
• Use the stage clips to hold the slide in place.
• Looking through the eyepiece, slowly turn the coarse adjustment knob until the
specimen comes into focus.
- Switching Objectives
• Look at the microscope from the side.
• Carefully revolve the nosepiece until the high-power objective lens clicks into place.
Make sure the lens does not hit the slide.
• Looking through the eyepiece, use the fine adjustment knob until the specimen
comes into focus.