This introduces students to Locard and the Locard Principle. It also includes a lab with the Claim-Evidence-Reasoning format.
Notes provided: The teacher is given choices on what evidence can be used in class for the lab. I've modified the evidence I've used over time, starting with them wearing t-shirts all day, then bringing them back to look for trace evidence. That didn't work very well, so I changed to evidence in baggies on socks, etc.