Introduction Forensic chemists test the physical and chemical properties of materials found at a crime scene. They also do similar tests on the materials found on a suspect’s skin or clothing. In this lab, the properties of three known materials will be compared with two samples of “evidence.” The materials and equipment used are less complex than those used by forensic chemists, but the overall method will be similar to the methods they use. The question this experiment attempts to answer is whether the properties of similar-looking materials can be used to tell them apart. Experimental First a well plate was obtained, and it was cleaned and dried as necessary. A spatula was used to place a small amount of cornstarch in each of three wells, and the physical properties of the cornstarch was observed and recorded. A clean spatula was then used to place a small amount of baking soda in each of three new wells, and the physical properties of the baking soda was observed and recorded. Next, a clean spatula was used to place a small amount of baking powder in each of three new wells. The physical properties of the baking powder that was observed was recorded. One well containing each substance was filled with water, and any changes that occurred were recorded. Then one unused well containing each substance was filled with vinegar, and any changes that occurred were recorded. Add …show more content…
After comparing the data collected, one will see large similarities between the baking soda and the crime scene sample. These are believed to bet the same substance. The same is true of the baking powder and the sample from the suspect's shoe. They also appear to be the same substance. Based on the difference in reactions to the other substances, one would conclude that the sample from the crime scene and the sample from the suspect’s shoe are not the same