MICRO LAB 1

Identify 3 ways in which the resolution of an image can be improved. (Hint: several involve light)

1. increase light by opening iris-diaphragm, 2. use immersion oil, 3. raise or lower the condenser 4. use lower magnification

Briefly explain why it is important to center your specimen in your field of view before moving to the next higher objective lens.

Because as magnification increases, the field of view decreases. If specimen is not centered it may be out of your field of view when moving to next higher objective.

What are the specific bacterial cell shapes for E. coli and Staph. aureus? Be sure to use correct terminology and to specify which shape is specific for which bacteria

E. coli = bacilli, Staph. aureus = cocci

a million microns in a meter

How big is a micron in comparison with a meter?

What is the numerical aperture and how is it related to resolution?

It is the light gathering ability of the lens. NA increases as magnification increases to compensate for poor resolution

The compound light microscopes we used in lab are parfocal. What does this mean?

That when you focus the image on the lowest objective, it mostly stays in focus in the next higher objectives.

Which part of the compound microscope is used to concentrate the light by directing light to form a cone? How should this part of the microscope be adjusted when increasing magnification?

The condenser. It should be raised as you increase magnification.)

What is the total magnification when using the high dry objective lens? Please show your calculation.

The total magnification when using the high dry objective lens is 400x. This means that the image will be magnified a total of 400 times the actual size. The objective magnification is 40x and the ocular magnification is 10x, so when you multiply these values together you get a total magnification of 400x.

Briefly explain the purpose of immersion oil. For which power objective lens is it used?

To prevent diffraction of the light or to gather the light. Used with 100x objective

light gathering capacity of the lens

What is the numerical aperture and how is it related to resolution?

yes, 0.5 microns

can you observe a virus using a compound microscope? what is the typical size of a virus?

800 x T.M

for a compound light microscope, what is the total magnification if using an objective lens with 200x magnification?

scanning objective

for which objective would you need the most light to view a specimen?

Briefly explain image inversion. Relate your answer to how image inversion affects the letter "e" as it is viewed with the compound microscope.

image inversion means that the image you observe in the compound microscope is backwards and upside down.

When switching from the 10x objective lens to the 100x objective lens, what happens to the size of image you are observing? Does the resolution of the image improve or worsen?

the image gets larger and increases in magnificiation but the resolution gets worse

To prevent the loss of light, and oil has the same refractive index as glass

what is the purpose of the oil immersion lens? how does it increase light?

the compound microscope

what microscope is used most commonly in the clinical laboratory?

when magnification increases in order to improve resolution

when and why would you need to increase light when viewing a specimen?

for personal preference, it does not affect resolution

when would the Illuminator be adjusted?

course/fine adjustment knob, illuminator, stage adjustment dials (2)

which mechanical parts of the microscope are adjustable?