Lab 2

Iris diaphragm knob?

adjust the amount of light a specimen receives

The 40x lens is called the "High dry" lens. Why do we call it that?

highest objective we have before adding an oil/liquid

What are two functions of the ocular lens

magnifies specimen, measure obeject

which objective lens will be used the most and why

10x100 because bacteria is very small and the oil immersion lens has the highest magnification

if you are using the oil immersion lens to view your bacteria, what is the total magnification?

1x100=1000

Function of condenser

Concentrates the light

Resolution

Provide detail to image of object

why must we use the immersion oil to get good resolution with the 100x lens?

it cuts down on the amount of refracted light and gives a better resolution. If there is no oil present light would go through the glass and into the layer of air, which would cause the light rays to bend and become lost

What does this measurement mean?

it magnifies the object to appear bigger, greatest magnification and will be used to look at very small organisms

Magnification

what makes the image of the object appear closer

before putting microscope away, name 2 things you must do

wipe the lens off, make sure there is no oil make sure it is being stored with the red lens down

If 50 ocular micrometer divisions = 5 stage micrometer divisions and if one division of the stage micrometer= .1 mm. The cells you measure are 42 ocular micrometer divisions long. Therefore how long are the cells?

-10 ocular micrometer divisions= 1 stage micrometer divisions -42 ocular micrometers = 4.2 stage micrometer divisions -4.2 stage micrometers= .42 mm

Define Parfocal. How does this characteristic affect the way you would view a slide?

-Parfocal means that once the image is in focus, it should remain in focus when switching to different objectives. After the image is in focus you should only adjust the fine focus.