In recent years, there has been an explosion of crime scene investigation shows. These shows are fun to watch, but you may be surprised to find out that CSI is all based upon chemistry and chemical reactions. The field of forensic chemistry has exploded in recent years. Forensic chemistry applies the principles of chemistry to assist in the solving of crimes. From fingerprinting to the identification of illegal drugs, forensic chemistry has completely altered the way in which our crime system operates. In this lab, you will be using forensic chemistry to help identify fingerprints and the presence (or absence) of blood.
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One of the earliest tools that emerged from forensic science. Initially, fingerprinting involved only dusting of surfaces in order to reveal any fingerprints that may be present. The problem with dusting is that is misses the majority of the fingerprints that are present on the surface. There are three major tests that are used to detect fingerprints:
The other test that you will be performing during this lab is the Kastle-Mayer Test. This test allows for the detection of blood and allows for us to determine that a sample is blood and not other substances that can sometimes looks like blood (i.e. paint, rust, ketchup, etc.). This test utilizes phenolphthalein in order to identify blood. If blood is present on a substance, then the presence for the hemoglobin molecule that is found in blood can be identified (and thus demonstrating that blood is present on the surface). The hemoglobin enzymes will break apart hydrogen peroxide (H2O2). This breaking apart can then be detected if phenolphthalein is present too. This is due to the fact that if blood is present and we have ran this test, then the solution will turn a bright pink. This bright pink will demonstrate that the solution is blood and not some other solution. If it is another solution, then the hemoglobin enzymes are not present is not present and, thus, the hydrogen peroxide is not broken down. This means that the pink color will not appear due to the fact that this breakdown did not occur. |
To find a list of materials and background information for this lab please click here:
CSI Part I CSI Part II CSI Part III CSI Part IV CSI Part V CSI Part VI CSI Part VII CSI Part VIII You are going to design two labs that test the following ideas:
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