Exercise 1 Flashcards
Know the parts of the microscope and their uses.
Ocular lenses: lenses closest to eye, typically magnify 10X.
Ocular width adjustment: Adjustment for your eye span.
Revolving nosepiece: Can be rotated to change from one objective to another.
Objective lenses: 4X (very low power), 10X (low power), 40X (high power); and 100X (oil immersion)
Stage adjustment knobs: Moves the slides on two horizontal planes: back and forth and side to side.
Mechanical stage: Provides movable platform for slide, to change field of view.
Iris diaphragm or aperture diaphragm: Opens or closes the diaphragm to control the amount of light sticking the objective. Improper illumination is a common problem as the light must be increased as magnification increases.
Condenser: Condeses light waves into a pencil shaped cone, thereby preventing the escape of light waves. It’s ideal position is just beneath the stage.
Condenser knob: Raises and lowers condenser. For this course the condenser should be all the way up.
Light control: Turns light source on and off. The degree it is turned on determines the intensity of light.
Coarse adjustment knob: Moves stage up and down rapidly for purposes of approximate focusing. Should only be used with lower power objectives.
Fine adjustment knob: Moves the stage up ans down very minutely for purposes of definative focusing.
What is magnification?
It is enlargement of objects. The total magnification is the product of the objective lens and the ocular lens. Typically 4X,10X, 40X, if 100X on the objectives; 10X on the oculars.
What is magnification?
It is enlargement of objects. The total magnification is the product of the objective lens and the ocular lens.
What does parfocal refer to?
It refers to the microscopes ability to remain in approximate focus when switching from one objective to another.
What is working distance?
It refers to the distance between the specimen and the objective.
What is refractive index?
Oil has the same refraction index as glass so diffraction of the light does not occur.
Understand the purpose of immersion oil with the 100x objective.
The main effect of the immersion oil is to collect aberrant light rays and allow them to enter the objective. Aberrant light rays are those that would otherwise be lost due to diffraction.
Be able to determine total magnification with oculars or objectives of varying magnifications.
Typically 4X,10X, 40X, if 100X on the objectives; 10X on the oculars. So you will multiply them.
Understand advantages/disadvantages of using a wet mount or a fixed smear to observe microbes.
A wet mount typically dries after 30-60 minutes, so it cannot be used over a long period of time. It can only be observed using the 10X and 4
Understand advantages/disadvantages of using a wet mount or a fixed smear to observe microbes.
A wet mount typically dries after 30-60 minutes, so it cannot be used over a long period of time. It can only be observed using the 10X and 40X objectives. However, a wet mount enables the viewer to study living microorganisms and obtain information about natural pigmentation and motility.
Know how to use the microscope and how to take care of it.
N/A
