Microscopy Principles and Practice

Practice flashcards covering microscope components, functions, care instructions, operating procedures, magnification formulas, working distance, field of view, and optical concepts.

What is a microscope defined as in the notes?

A tool used to magnify an object that is unable to be viewed by the unaided/naked eye.

What is the definition of magnification?

The act of making the view of an object larger.

What is the definition of resolution?

The clarity of the object being viewed.

What is the proper procedure for carrying a microscope?

ALWAYS carry the microscope with one hand underneath the base and the other arm on a stable part of the arm, and NEVER carry it with one hand.

What materials should be used to clean microscope lenses?

Use lens paper and lens cleaner to remove smudges, and NEVER use cloth that can scratch lenses. Clean oculars before and after use.

What is the function of the base of a microscope?

It is the supportive bottom piece of the microscope.

What is the function of the substage light on a microscope?

It serves as the light source for illumination of the specimen, controlled by a switch, with intensity controlled by a light intensity knob or rheostat.

What is the head of a microscope?

The upper part of the microscope that contains the viewing pieces, including the lenses and nosepiece.

What are ocular lenses and what is their typical magnification?

They are the eyepieces located on the head, usually having a $10\text{x}$ magnification.

What is the revolving nosepiece?

A structure located below the ocular lenses that serves as the attachment site for the objective lenses and allows for rotation between them.

What are the standard objective lens magnifications described in the notes?

Scanning lens ($4\text{x}$), Low Power lens ($10\text{x}$), High Power lens ($40\text{x}$), and Oil immersion lens ($100\text{x}$).

What is the function of the arm of a microscope?

It is the connection piece between the base and the head.

What is the stage of a microscope?

The flat platform connected to the arm and suspended under the objective lenses, where the slide to be viewed is placed.

How does the coarse adjustment knob function, and when should it be used?

It is the larger knob that raises or lowers the stage in large increments, and it is ONLY used during scanning ($4\text{x}$) or low power ($10\text{x}$).

How does the fine adjustment knob function?

It is the smaller knob that raises or lowers the stage in small increments to make the image sharper and increase the resolution of the specimen.

What is the function of the condenser on a microscope?

A group of lenses that concentrates the light from the substage light source to the slide.

What is the function and location of the iris diaphragm?

Located underneath the condenser, it regulates the amount of light passing through the condenser to help with resolution and light contrast of the specimen.

How is total magnification calculated for each objective lens using a $10\text{x}$ ocular lens?

Total magnification is the ocular lens magnification ($10\text{x}$) multiplied by the objective lens magnification: Scanning ($4\text{x} \times 10\text{x} = 40\text{x}$), Low Power ($10\text{x} \times 10\text{x} = 100\text{x}$), and High Power ($40\text{x} \times 10\text{x} = 400\text{x}$).

What is working distance, and how does it change as magnification increases?

Working distance is the amount of space between the objective lens and the slide, and it decreases as magnification increases.

What is field of view, and how does it change as magnification increases?

Field of view is the amount of the slide that is visible looking through the microscope, and it decreases as magnification increases.

What does it mean that microscopes are parfocal?

It means that once objectives are switched, there is little refocusing required.

What is the proper procedure when finished observing a slide?

Use the revolving nosepiece to switch to the scanning $4\text{x}$ objective, use the coarse adjustment knob to lower the stage all the way down, remove the slide, clean the microscope, turn off the power, unplug and wrap the cord, and cover the microscope.