Forensic Science Study Guide- Soil and Glass

1. Describe how soil is made and what factors effect the creation of soil.

2. Who was the first forensic scientist to say that there should be study of soil?

He observed “Dirt on shoes can often tell us more about where the wearer of those shoes had last been than toilsome inquiries.”

3. When was soil first used in a criminal case?

4. What percentage of the earth contains soil for us to study?

5. What are the 3 main grain sizes and 3 subcategories of soil?

6. Define humus, and where is it located in relation to other horizons of soil?

7. What is soil horizon?

8. What factors can affect the pH of soil?

9. What physical factors do investigators look at when they are studying soil?

10. What chemical factors do investigators look at when they are studying soil?

11. Why is evidential value of soil so good? How can soil be individualized as evidence?

12. What different kinds of rocks are found in soil?

13. What is palynology?

14. What causes sand to have different colors?

15. How does water affect the shape of sand?

16. How long does it take for sand to form naturally?

17. List the differences between continental, volcanic, skeletal, and precipitate sand.

18. How can sand be classified as individual evidence?

19. When was glass first created?

20. What is glass made of? How is it made?

21. What does it mean when glass is described as an “amorphous solid”?

22. List and describe the 6 different types of glass.

23. Which type of glass is most common? Which type of glass is most expensive?

24. How is density calculated?

25. What is a refractive index?

26. Describe the immersion method for determining refractive index. How does a Becke Line relate to this method? When do you know a substance has reached it’s match point with a liquid?

27. Why do concentric circles form when glass is fractured?

28. Draw a fracture pattern including two POI, concentric cracks, radial cracks, and stress lines.

29. Which type of fracture is formed first? Which type of fracture is formed on the same side of the force? Which is formed on the opposite side of the force?

30. How can you determine which fracture occurred first?

31. Define: concentric crack, radial crack, stress line, hackle, ream, and Wallner line.

32. How does a bullet’s angle of entry change glass shatter patterns?

33. How can glass fracture patterns be individualized?

34. What is backscatter?