Crime Scene Investigation Crime Scene Investigators: Alex Linton, Dhruv Mathur, Alex Abraham
Problem • Your team is being called as CSI expert witnesses at a trial. You need to prepare a presentation to prove to a jury the identity of the evidence (matter) found at a crime scene. Use your expertise of physical & chemical properties in your presentation.
Physical Properties • Physical Properties- A characteristic of a substance that does not involve a chemical change, such as density, color, or hardness • Examples of physical properties: • Ductility- To be pulled into a wireMalleability- To be rolled or punched in thin sheets • Density- The mass per unit volume of a substance
Chemical Properties • Chemical properties are the properties of an item relating to how it reacts to certain things, such as heat and electricity. • Some examples of these are:FlammabilityCombustibilityOxidation
Matter • Matter is anything that has mass and takes up space • Does it have volume (does it take up space)? • Does it have mass (is there something measurable that isn’t energy in the space [atoms, molecules, etc.])? • All of our mystery substances are made of matter.
Metal 1: Aluminum • Metal 1 is non-magnetic • We determined that metal 1 is aluminum • Density is 60/37g/cm3 • The physical properties of aluminum are the boiling point, the melting point, and density • The chemical reactions of aluminum with air is oxidization • The chemical reactions of aluminum with water is oxidization • The chemical reactions of aluminum with acids is a slower dissolving rate
Metal 2: Steel • Metal 2 is magnetic • We determined that metal 2 is steel • Density is 25/13g/cm3 • The physical properties of steel are the boiling point, the melting point, and density • The chemical reaction of steel with air is oxidization and flaking • The chemical reaction of steel with water is oxidization and rusting • The chemical reaction of steel with acids isa faster dissolving rate
Liquids in question: • Water-nonflammable, not combustible, will oxidize. Clear, not very viscous, nontoxic. • Vinegar-nonflammable, not combustible, will oxidize. Clear, not very viscous, nontoxic. • Alcohol-flammable, combustible, will oxidize. Clear, not very viscous, mildly toxic.
Conclusion • In conclusion: • Metal 1 was aluminum • Metal 2 was steel • Mystery Liquid was alcohol • Mystery Powder was baking powder
Source Citations • www.webelements.com • http://www.ehow.com/list_6591046_science-activities-matter.html • http://www.elmhurst.edu/~chm/vchembook/104Aphysprop.html • Science Textbook