Page 23 - The Smoking Gun Gunshot Residue
P. 23
Lab
Procedure
5. Place one drop of the diphenylamine solution on
Part 1: the second alcohol swab and observe the
Gunshot Residue reaction immediately. If a blue color change is
observed, the test has detected nitrates on the swab.
Detection Test
6. Repeat this testing procedure for the negative
control and the evidence foam swabs.
1. Obtain the foam swabs collected from all crime
scenes and the positive and negative controls. 7. Record the results from each swab.
2. Starting with the positive control foam swab, 8. When finished with your experiment,
place two alcohol swabs on a clean, flat surface, formulate a hypothesis as to the events
such as the bottom of a Petri dish or a weigh surrounding the crime.
boat.
3. Rub one side of the positive control foam swab
onto the first alcohol swab. Flip the foam swab ACTIVITY 1:
to the other side and repeat the procedure with SCANNING ELECTRON
the second alcohol swab. MICROSCOPE
4. Place one drop of sodium rhodizonate on the View the video clips to learn about
first alcohol swab and observe the reaction. the operation of the Scanning Electron
If a red color change is observed, one of the microscope and to look at actual gunshot
metals specific to gunshot residue has been residue evidence.
detected.
THE MYSTERY OF LYLE AND LOUISE 23
