Microbiology: Microscopy and Calibration

What is the light path?

Light source → stage → slide → objective → ocular lens → eyes

What is brightfield microscopy?

helps identify microbes from the environment or specimen

What is resolution?

What is resolving power?

is how apart two points have to be for a microscope to show them as separate

What is resolution?

lens ability to sep/distinguish 2 objects from each other, rather than single larger object

What is total magnification?

objective lens * ocular lens

What is field of view

diameter of the visible area you can see when looking through the eyepiece, typically measured in millimeters

what is depth of field

range of distance within which objects appear in sharp focus

What is working distance?

space between the front edge of the objective lens and the specimen surface when the specimen is in focus

What is parfocal?

stays in focus when using magnification

what is refraction?

bending of light as it passes through different lenses, allowing for the magnification and clearer visualization of specimens

What is an ocular micrometer?

a microscope eyepiece ruler

When would you use an ocular micrometer?

measuring an organism

What is a stage micrometer?

attune ocular micrometers and is a microscope slide has 10 micrometer and 100 micrometer markings

When would you use a stage micrometer?

for calibrating measurements before using stage micrometer

How do you calibrate the ocular micrometer?

using the stage micrometer

How do you determine the value of an ocular unit on your microscope?

um/OU

Why must calibration of the ocular micrometer occur for every objective?

because every objective lens has a different magnification, so the field of view is different.

If you have a distance of 900 um lining up with 33 lines of the ocular micrometer, what is the value of an ocular unit for that microscope?

27.3 um/OU

If you have a distance of 250 um lining up with 15 lines of the ocular micrometer, what is the value of an ocular unit for that microscope?

16.7 um/OU