Lab Ex 3 Microscope Review

Question 1

Light microscope

Answer 1

coordinated system of lenses arranged to produce an enlarged, focusable image of a specimen

Question 2

Magnifies

Answer 2

increase in apparent size

Question 3

Resolution

Answer 3

ability to distinguish 2 points as separate points

Question 4

Contrast

Answer 4

amount of difference between the lightest and darkest parts of an image

Question 5

Light Source

Answer 5

lightbulb located at the base of the microscope; illumunates the specimen by passing a light through a thin, almost transparent part of the specimen

Question 6

Condenser Lens

Answer 6

located immediately below the specimen, focuses light from the light source onto the specimen

Question 7

Condenser Iris Diaphragm

Answer 7

just below the condenser; knurled ring/lever that can be open/closed to regulate the amount of light reaching the specimen; when open, image will be bright; when closed, image will be dim

Question 8

Objectives

Answer 8

3-4 lenses mounted on a revolving nosepiece; each = series of several lenses that magnify the image, improve resolution, and correct aberrations in the image; can be low (4x), medium (10x), high (40x), or oil immersion (100x)

Question 9

Ocular

Answer 9

lens that you look through; magnifies the image 10x

Question 10

Monocular

Answer 10

microscopes with one ocular

Question 11

Binocular

Answer 11

microscopes with 2 oculars

Question 12

Body Tube

Answer 12

metal casing through which light passes to the oculars

Question 13

Stage

Answer 13

secures the glass slide on which the specimen is mounted

Question 14

Parfocal

Answer 14

most light microscopes are this; image will remain nearly focused after the 40x objective lens is moved into place

Question 15

Parcentered

Answer 15

Most light microscopes are also this; image will remain centered in the field of view after the 40x objective lens is in place

Question 16

Fine Adjustment Knob

Answer 16

to fine-focus the image, turn this; changes the specimen-to-objective distance slightly and therefore makes it easy to fine-focus the image

Question 17

Field of View

Answer 17

area you can see through the ocular and objective; helps you determine the approximate size of an object you are examining; can be measured with ruled micrometers

Question 18

Ocular micrometer

Answer 18

small glass disk with thin lines numbered and etched in a row; lines superimpose on the image and allow you to measure the specimen

Question 19

Stage micrometer

Answer 19

glass slide having precisely spaced lines etched at known intervals

Question 20

Depth of Field

Answer 20

thickness of the object in sharp focus; varies with different objectives and magnifications

Question 21

Wet Mount

Answer 21

fresh preparation of a slide to be viewed with a microscope

Question 22

Dissecting (Stereoscopic) Microscope

Answer 22

offers advantages over a compound microscope like a better working distance; can be used to view opaque objects or those that are too large to see with a compound microscope; always binocular; disadvantages: lower resolution and magnification than a compound microscope (4 - 50x)

Question 23

Working Distance

Answer 23

distance between the objective lens and specimen