Chapter 2: Types of Microscopes

Question 1

Bright-field Microscope

Answer 1

Forms its image when light is transmitted through the specimen; produces image that is darker than the surrounding illuminated field.

Question 2

Dark-field Microscope

Answer 2

Puts a “block” on a bright-field microscope that blocks all light from entering the objective lens except peripheral light; creates image of brightly illuminated specimens surrounded by a dark field

Question 3

Phase-Contrast Microscope

Answer 3

Transforms subtle changes in light waves passing through specimen into differences in light intensity (different parts of specimen have different densities); best for internal detail

Question 4

Interference Microscope

Answer 4

Manipulates light like phase-contrast but adds contrasting colors to the image and two beams of light rather than a single one; produces extremely well-defined images that are vividly colored and appear 3-D

Question 5

Fluorescent Microscope

Answer 5

Modified compound microscope with an Ultraviolet radiation source and a filter that protects the viewer’s eye; specimen must be coated with a source of fluorescence

Question 6

Confocal Microscope

Answer 6

Overcomes problem of cells or structures being too thick causing microscopes to have trouble focusing; Uses a laser beam of light to scan various depths in the specimen; captures highly focused view at any level

Question 7

Transmission Electron Microscope

Answer 7

Produces image by transmitting electrons through the specimen; specimens must be sectioned in extremely thin slices and stained or coated with metals

Question 8

Scanning Electron Microscope

Answer 8

Bombards surface of a whole metal-coated specimen with electrons while scanning back and forth over it; electron pattern is displayed on a TV screen; color is added afterwards