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Suports the microscope.
the bottom of the microscope that sits on the table
Substage light or mirror
located in the base. In microscopes with a substage light source, the light passes directly upward through the microscope: light controls are located on the microscope base. If a mirror is used, light must be reflected from a separate free-standing lamp.
The platform the slide rests on while being viewed. The stage has a hole in it to permit light to pass through both it and the specimen.
stage clip that can be used to secure the slide on the stage.
Small substage lens that concentrates the light on the specimen.
Iris diaphragm lever
Arm attached to the base of the condenser that regulates the amount of light passing through the condenser. The iris diaphragm permits the best possible contrast when viewing the specimen.
Coarse adjustment knob
Used to focus on the specimen.
- The larger of the two, will move the stage or objective lens (depending on the microscope) up and down quickly and quite visibly, altering the distance between them. It is very important that the coarse focus knob is only used
- with the low power or scanning objective lenses, otherwise the microscope or objective lenses could be damaged. Adjust the coarse focus knob to observe how quickly the focal distance changes.
Fine adjustment knob
Used for precise focusing once coarse focusing has been completed.
- will move the stage or objective lens such a small amount that it is hardly noticeable
- to the naked eye. This is the knob you will use to get the perfect focal distance so the image will be crystal clear.
Head or body tube
suports the objective lens system (which is mounted on a movable nosepiece) and the ocular lens and lenses.
- vertical portion of the microscope connecting the base and head.
- is the vertical framework ascending from the base along the back of the microscope. When handling the microscope always hold the arm while supporting the base with your other hand.
Ocular (or eyepiece)
one or two lenses at the superior end of the head or body tube. Observations are made through the ocular(s). An ocular lens has a magnification of 10x.
used to indicate a specific area of the viewed specimen, it is attached to one ocular and can be positioned by rotating the ocular lens.
rotating mechanism at the base of the head. use the nosepiece to change the objective lenses. Do not directly grab the lenses.
Adjustable lens system that permits the use of a scanning lens, a low-power lens, a high-power lens, or an oil immersion lens. The objective lenses have different magnifying and resolving powers.
projected to the ocular.
seen by your eye.
- of any specimen being viewed is equal to the power of the ocular lens multiplied by the power of the objective lens used.
- magnificationofocular x magnificationofobjective = total magnification
resolution (resolving power)
the ability to discriminate two close objects as separate, is not. The more light delivered to the objective lens, the greater the resolution. The size of the objective lens aperture (opening) decreases with increasing magnification, allowing less light to enter the objective.
the area you see through the microscope.
describes the distance between the lens of a microscope and the top of the sample being observed.
depth of field
(the depth of the specimen clearly in focus) is greater at lower magnifications.
Who refined the methods of lens?
By 1609, Galileo Galilei
- Then: Dutchman Anton van Leeuwenhoek improved view objects in pond water
- – microorganisms – life at a tiny level.
- Finally:Robert Hooke improved the lens up to the point where he could see cells.
These lenses allow you to change the degree of magnification. Some of our microscopes have four objective lenses while others have only three.
Name the 4 different objective lenses and magnification
- -scanning "4x"
- -Low "10x"
- -high "40X"
- -oil immersion objective "100x"
This lens serves to capture and focus light from the lamp below onto the slide mounted on the stage. On many microscopes the condenser lens can be adjusted up or down with a knob beneath the stage.
is located within the condenser and is one of the most important pieces of the microscope, though it is often neglected by many students. The diaphragm allows you to adjust the amount of light passing through the slide by adjusting the diaphragm lever.
emits light to illuminate the specimen so that you can actually see something.
Field of view
(FOV) is the actual “circle” you see when looking in the microscope. Although this circular field of view appears to be the same no matter which objective lens you are using, this is not the case. The circular area you are actually viewing will decrease as you increase the magnification
depth of focus
decreases as the magnification increases as illustrated below: