End of Chapter - pnhs science

1 End of ChapterBibliography lists the sources for additional Studies provide stories based on topics for critical recaps the key points of the Chapter , linked to the learning highlight an occupation in forensics related to Chapter content. Neutron Activation AnalystA neutron activation ana-lyst applies techniques that can be used in many different fields, such as medicine, geology, engi-neering, and forensics. Given a sample of trace evidence, a nuclear acti-vation analyst bombards the sample with neutrons produced by a nuclear reactor.

2 Some atoms in the sample may absorb one of these neutrons and become radioactive sample gives off radiation of dif-ferent wavelengths, which the analyst measures to determine the elements contained within the sam-ple. Each chemical ele-ment gives off radiation of a specific wavelength. The amount of radiation at a certain wave-length can indicate the amount of the element in the sample. Instrumental neutron activation analysis is a very sensitive technique that can detect chemicals that other methods cannot.

3 In addition to being very sensitive, neutron activity analysis requires a very small sample, does not destroy the sample, and is very neutron activation analysis is a powerful technique that would be useful in help-ing to solve many crimes, most laboratories cannot perform this type of analysis, because it requires a nuclear reactor. One laboratory that does have the facilities to perform neutron activation analysis is the Radiation Center at Oregon State University. Police departments have called on analysts there to help solve crimes by ana-lyzing trace evidence, such as glass activation analy-sis does not work as well on paint chips and human hair, because these types of samples are porous and can absorb contaminants from the environment.

4 Besides glass evidence, this analysis also works well on bullets. A neutron activation analyst can use this technique to match a bullet found at a crime scene to a bullet found in a suspect s posses-sion, even when the police have not found a gun con-nected to the crime. The material used to make bullets contains varying amounts of several elements, such as arsenic, copper, silver, tin, mercury, or gold. The exact chemical composition of a bullet made in one batch is different from that of a bullet made in a different batch.

5 According to one analyst there is only one out of 10,000 chance that a bullet from one batch will match a bullet from a differ-ent batch of bullets. An analyst from the Radiation Center at Oregon State University was able to determine the exact chemical composition of bullets found at the scene of a murder and link the bullets to bul-lets found at a suspect s home. These findings helped convict the suspect on three counts of aggravated murder. The suspect was sentenced to life in prison without Evidence423 Learn More About ItTo learn more about a career as a neutron activation analyst, go to or FalseCHAPTER 17 REVIEW 1.

6 The lands and grooves of a barrel s rifling improve the accuracy of a bullet. 2. The caliber of a cartridge is always measured in one-hundredths of an inch. 3. Firing pin marks are found on the back of the bullet. 4. Lands and grooves help match a crime-scene bullet with its shell casing. 5. The amount of gunshot residue on a victim is usually proportional to the distance between the victim and the Choice 6. Shotguns are examples ofa. handgunsb. long gunsc. revolversd. semiautomatic weapons 7. Which of the following best describes the trajectory of a projectile?

7 A. the height of the shooterb. the path of the flight of a bulletc. the housing for the bullet s gunpowderd. the pattern of lands and grooves on the projectile 8. Which of the following is not part of a cartridge?a. barrelb. bulletc. gunpowderd. primer powder 9. The caliber of a bullet is related to itsa. diameterb. lengthc. speedd. weight 10. Semiautomatic pistols store cartridges in aa. magazine (clip)b. cylinderc. firing pind. muzzle1011121314151617 BibliographyBooks and JournalsDavid, A. J., and L. Exline. Current Methods in Forensic Gunshot Residue Analysis.

8 Boca Raton, FL: CRC Press, Maio, Vincent J. Gunshot Wounds: Practical Aspects of Firearms, Ballistics, and Forensic Techniques. Boca Raton, FL: CRC Press, , Colin. The Casebook of Forensic Detection: How science Solved 100 of the World s Most Baffling Crimes. New York: Berkley Trade, , Brian J. Handbook on Firearms and Ballistics: Examining and Interpreting Forensic Evidence. Boca Raton, FL: CRC Press, , Arthur J. Modern Practical Ballistics. Minneapolis, MN: Kenwood Publishers, , Richard. Crime Scene. Englewood Cliffs, NJ: Prentice Hall, Forensic science eCollection.

9 , Paul. Uncovering Convincing Evidence, , Oct. 30, site references call attention to the additional resources on Review provides true or false, multiple choice, and short answer questions for student to Use This BookxixActivitiesForensic Anthropology: What We Learn from Bones393 ACTIVITY 13-3 THE romanovs AND DNA: AN INTERNET ACTIVITYO bjectives:By the end of this activity, you will be able to:1. Examine how the Romanov family was identified from their Describe what the remains revealed about the family s Describe how DNA technology was used to help identify the skeletal remains of the Romanov Precautions:NoneTime Required to Complete Activity:Part A: 40 minutesPart B: 30 minutesPart C: 60 minutesMaterials:access to the Internetpen and paperPart A:Procedure:1.

10 Open the Internet and type in the Internet site: Refer to the menu bar at the far left of the page and double-click on the fifth heading: Use the scroll bar to the right to pull the screen down. At the bottom of the screen, double-click on the second module entitled recovering the romanovs . 4. Move the scroll bar up to the top of the screen to double-click on the Romanov Move the scroll bar down to the bottom of the screen. You will see 10 circles. Click on each numbered circle and answer the questions as you progress through the material.