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A window is broken. The group of vandals who were standing behind the broken window run away. If the broken glass projected inward, how is it possible that a small amount of trace broken glass evidence was found on their clothes?

1. Did the density of the glass found on any of the four suspects match the density of the glass found at the crime scene? Explain your answer. 2. Check your results with your classmates. How did your results compare to those of the rest of the class?

1. Suggest other liquids to test for refractive index that you think might give you a higher refractive index than any of the liquids selected in this experiment. 2. As the thickness of the liquid increases, what effect might that have on the bending of light? Will the bending become more pronounced or less pronounced?

1. Why would the match of glass from a crime scene and a suspect be considered to be class evidence? 2. Explain refraction of light. Include in your answer the following:  two different mediums  light velocity density

1. A refractive index of olive oil is equal to 1.47. It is calculated as a ratio between what two numbers? 2. List five different characteristics to note when comparing a tire from a suspected tire to the tire mark found at the crime scene.

Do further research on imprint or impression evidence in the O.J. Simpson or Ted Bundy cases, or research case studies not mentioned in the text that had their cases resolved as a result of impression or imprint evidence. Submit a written report on your findings.

Tire impressions of a tire must be made using the complete rotation of a tire. Explain why this is important if the tire impression is to be compared with a photograph of a tire impression found at a crime scene.

Describe how you could distinguish the teeth of an adult from the teeth of a teenager or child. Dispose of unused Plaster of Paris in a garbage container; do not dump it down the sink drain!

Thoroughly wash all equipment as soon as possible after use. After dumping out any excess Plaster of Paris, allow the remaining plaster to dry. The old plaster can be removed after it dries by pounding on the sides of the plastic coffee can.

Work outside if conditions permit. If you are working inside, use newspaper to line any desktops. The sand can scratch the surface of some countertops. Wear safety goggles when mixing Plaster of Paris and when using the hairspray. The spray can also irritate some people’s throat and nasal passages.