The Killers Trail The Product Rule Forensic Science

The Killer’s Trail The Product Rule Forensic Science 9/17/15

Drill: What evidence would you collect? Make a list of items and what you could find on/from them. Mock Crime Scene: http: //www. masss. gov

Objectives • SWBAT • Name many forms of physical evidence. • Classify evidence as indirect (circumstantial) or direct. • Classify evidence as individual or class. • Examine the death of Marilyn Sheppard. • Calculate the probability of various events using the Product Rule.

The Killer’s Trail • You need: • The Killer’s Trail WS • You will watch “The Killer’s Trail” and answer questions about it. Also, whenever you hear a new piece of evidence mentioned, write it down on the back of your question sheet.

Sam Sheppard Trial Evidence • What kind of evidence did you write down? • Testimonial/ Direct • Physical/ Indirect • Come up to the board and write types of physical evidence • Class or individual? How was it useful?

What good is class evidence? • The product rule is a formula for determining how frequently a certain combination of characteristics occurs in a population. • It is usually used for combinations of genetic traits.

Example • 70% of people can roll their tongue • 14% of people think cilantro tastes like soap • 1 in 12 men is colorblind, 1 in 250 women is colorblind. • What is the likelihood of • A colorblind man who can roll his tongue and thinks cilantro tastes like soap? • A non-colorblind woman who can roll her tongue, and thinks cilantro tastes fine?

Worksheet • Turn to pg. 3 in your packet – Product Rule • Note that these are VERY small percentages • 3. 6% = 0. 036, not 0. 36 • When done, let’s put these on the board. • Don’t worry about sig figs—round answers to two digits. • (I know, Chem folks. It hurts me, too. )

Closure • Choose an object. • List the individual and class evidence about that object. • Is there any evidence (fingerprints? ) that could be identified? Compared?