FRSC 2001 – Introduction to Forensic Science Technology I
Homework Assignment #3 – 20 points total
Name
Due by 3PM Thursday 2/12 (Monday Section) or by 3PM Monday 2/16 (Wednesday
Section) to the blue box outside of PHS 306
Provide a complete answer to each of the following questions on the topic of Microscopy in the
Crime Lab:
1. A compound microscope works by combing the images produced by two different lenses. One
called the
lens is near the specimen. This lens produces a
(real or virtual?) image. That image is then further magnified by a second lens near the
viewer called the
lens. This lens produces a
(real or
virtual?) image that is viewed by the user.
2. Explain how the total magnification is calculated on a compound microscope.
3. Define the following terms:
a. Resolution
b. Empty magnification
c. Depth of field
d. Field of view
4. List at least two advantages and at least two disadvantages to using a compound microscope
to view objects.
5. Describe two different specific items of evidence that would likely be examined using a
compound microscope in the forensic analysis of physical evidence.
6. Explain how a stereomicroscope differs from a compound microscope.
7. List at least two advantages and at least two disadvantages to using a stereomicroscope to
view objects.
8. Describe two different specific items of evidence that would likely be examined using a
stereomicroscope in the forensic analysis of physical evidence.
9. What is the difference between transmitted light and reflected light in optical microscopy?
10. List two specific types of physical evidence that are best viewed under transmitted light and
two specific types of physical evidence that are best viewed under reflected light.
11. Describe how a comparison microscope works. That is, how is one able to view two images
side-by-side at the same time?
12. Describe two different specific items of evidence that would likely be examined using a
comparison microscope in the forensic analysis of physical evidence.
13. Explain how the comparison microscope is linked to examination of physical evidence from
the St. Valentine’s Day Massacre of 1929.
14. What is polarized light?
15. Provide a definition for the terms isotropic and anisotropic. List one example of a commonly
encountered type of physical evidence that is isotropic and one example of a commonly
encountered type of physical evidence that is anisotropic.
16. What does the term refractive index mean in both simple and mathematical terms?
17. Define the term birefringence and explain when it would be of significance to the forensic
scientist.
18. Explain the function of the polarizer and the analyzer in polarized light microscopy.
19. When looking through a polarized light microscope under crossed polars with no sample on
the stage, what does one see?
20. Explain why a forensic scientist see a series of brightly colored rainbow-like colors when
viewing a fiber sample under crossed polars on the polarized light microscope.