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Physical Properties: Glass and Soil

Read Chapter 4 text and PowerPoint to complete the following review questions:

1. Define the terms physical property and chemical property.

2. Why is the metric system of measurement easier to use than the ““English system””? Which system is used in the United States?
3. List the basic units of length, mass, and volume in the metric system.
4. What reference points are most often chosen when constructing a temperature scale?
5. List the two most commonly used temperature scales and their respective reference points.
6. Define weight and mass and explain the difference between the two concepts.
7. What is density? How does heat affect the density of gases and liquids?
8. Define the terms refraction and refractive index.
9. What is the difference between a crystalline solid and an amorphous solid? How does this difference affect the refractive index of each of these types of solid?
10. Explain how a prism disperses white light into its constituent colors.
11. Define intensive property and name two intensive properties of matter.
12. List two factors that make it difficult for criminalists to compare glass samples.
13. Describe the process of flotation and explain what it is used for.
14. What is the Becke line and how is it used to determine the refractive index of a glass sample?
15. What is the 3R rule and how is it applied to the analysis of glass fractures?
16. How can an investigator determine the order in which several successive penetrations of a glass occurred?
17. How can soil evidence be valuable even if the site of the crime has not been ascertained?
18. What is a mineral and how can minerals be important in the comparison of soil samples?
19. What is the most important consideration when collecting soil samples from a crime scene? At what locations should soil standard/reference samples be collected?
20. Why is soil collected from suspect automobiles left in lump form?