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Experiment 10

This document describes an experiment on identifying individuals who have fired guns using the paraffin test. The experiment involves taking paraffin casts of the hands of suspects, applying diphenylamine reagent to the casts, and observing any color changes which could indicate the presence of gunshot residue. The paraffin test is used to extract gunpowder particles from the skin that may be embedded from firing a weapon. The reagent reacts with nitrate compounds from gunpowder to potentially identify if an individual recently fired a firearm.

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Mama Choii
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216 views5 pages

Experiment 10

This document describes an experiment on identifying individuals who have fired guns using the paraffin test. The experiment involves taking paraffin casts of the hands of suspects, applying diphenylamine reagent to the casts, and observing any color changes which could indicate the presence of gunshot residue. The paraffin test is used to extract gunpowder particles from the skin that may be embedded from firing a weapon. The reagent reacts with nitrate compounds from gunpowder to potentially identify if an individual recently fired a firearm.

Uploaded by

Mama Choii
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
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Experiment #10

Paraffin Test

I. Objective
Learn how to identify if a person has fired a gun or not.

II. Apparatus/Materials
Metal tray, beaker (80 ml), medicine dropper, paraffin casts, Diphenylamine reagent

III. Procedure
1. Take the paraffin casts of the person who fired a firearm.
2. Place the paraffin casts in a metal tray.
3. Pour the DPA reagent in a beaker (80 ml). With the use of a medicine dropper, apply
the reagent to each of the paraffin casts.
4. Record and illustrate your observations.

IV. Observation
1. What is the difference between paraffin casting and paraffin test?

2. Why is there a need to conduct paraffin casting of the person who fired a firearm?
3. What is the basis in administering the paraffin test?

4. What is the use of Diphenylamine reagent?

5. What are the factors that will influence a negative gunpowder nitrate finding?

6. Why do most forensic laboratories around the world prefer to conduct gunpowder
residue examination using highly sophisticated laboratory instruments?

V. Post Laboratory Discussion


Guide Questions
1. What are the substances that leak out from the breech mechanism of a firearm
when it is fired?

2. When does gunpowder residue become embedded in the hands of the firer?
3. How are the gunpowder residues removed from the hands of the subject when
the melted paraffin wax is applied?

4. Describe the analytical paraffin wax used in paraffin casting?

5. What is paraffin casting?

6. What is produced after a person is subjected to paraffin casting?

7. What is extracted from the hands of the subject who fired a firearm once he is
subjected to paraffin casting?

8. When do you get a good paraffin cast?


9. Usually, how long will the gunpowder residue stay in the pores of the firer's skin?

10. How many days are required for a person to be subjected to paraffin casting?

11. Why is an embalmed cadaver, who is suspected to have fired a firearm, no


longer be subjected to paraffin casting?

12. How is paraffin casting conducted on the clothing of the victim to determine the
presence of gunpowder residue?

13. What is the basis for determining the approximate distance of the shooter to the
victim?
VI. Conclusion

VII. Illustration

VIII. Documentation

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