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This report details the evaluation of physical and chemical properties of various crime scene evidence gathered by CSI agents Kristin Shortal, Michel Sheaffer, and Alexis Schwebel. The analysis covers two metal samples—steel and aluminum—highlighting their density, magnetic properties, and reactions with elements like air, water, and acids. Additionally, it addresses the identification of a mystery liquid (alcohol) and a mystery powder (baking powder), alongside their observable reactions. Overall, the findings contribute to understanding the characteristics of collected evidence.
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Crime Scene Evidence Evaluation CSI Agents: Kristin Shortal Michel Sheaffer Alexis Schwebel
Physical Properties • A characteristic of a substance that does NOT involve a chemical change. • Physical properties are measurable and observable. • It can include look, taste, texture, sound, color, and smell.
Chemical Properties • Chemical properties are a property of matter that describes a substance’s ability to participate in chemical reactions • It can include mass, density, volume, height, reactants, and temperature.
Metals Sample #1 Sample #2
Metal Evidence Evaluation • Identity of sample #1: Steel • Supporting evidence: Measured the density, Conductive, Non-Flammable, Reactants- Air, Water, and Acids • Density of steel= 2.6 grams • It is magnetic. Source- http://www.webelements.com/iron/
Metal Evidence Evaluation • Identity of sample #2: Aluminum • Supporting evidence: Measured the density, is conductive, reactants are air, water, and acids, non-flammable. • Density= 2.1 grams • Non-magnetic • Source- http://www.webelements.com/aluminum/
Steel and Aluminum volume Density is the ratio of the mass of a substance to the volume of the substance. Aluminumis on the left and steelis on the right.
Density Video Steel Density= 2.6 grams Aluminum Density= 2.1 grams The first metal in the video is aluminum and the second is steel.
Magnetism Magnetism is the force of attraction or repulsion generated my moving or spinning electric charges. *The steel was magnetic, but the aluminum was not.
Aluminum and steel length Aluminum length: 2.2cm Steel length: 4.1cm
Liquid evidence evaluation • Identity of mystery liquid: Alcohol • Supporting evidence: Flammable, similar smell, similar density, same reactants.
Powder Evidence evaluation • Identity of mystery powder: Baking Powder • Supporting evidence: Fizzled with vinegar, blackened with iodine, had no reaction with water • The baking powder had the same reactions as the baking powder did.
Reactants From top to bottom: Baking Powder Baking Soda Baby Powder Corn Starch
Summary • The two metals that were found were aluminum and steel. • The mystery powder that was found was baking powder. • The mystery liquid that was found was alcohol.