You will need to provide the following materials for this lab:
You will need to set-up the following materials prior to lab:
Use the following key to check how each lipstick or envelope should be labeled.
I start each class period in this unit with a warm-up activity that targets forensic science concepts and other skills (observation, problem-solving, etc.) Not only does this get the students in the frame of mind necessary to address the field of forensics, but it also introduces key vocabulary they will use throughout the unit in a more relevant way. In addition, this activity allows students to refine their research skills as they perform quick internet searches to find the correct answers. By using the attached weekly Answer Sheet* and passing it out as they enter the classroom every Monday morning, not only can I save paper, but I can also provide a routine that allows students to begin without prompting, waiting for paper, or asking things such as, "What do we do?" and, "Where do we write our answers?"
After providing about 2-3 minutes to look for the answers, we go over them together and discuss the information provided. I help students to define key terms and providing background knowledge necessary to help students understand the questions. However, I do not spend as extended period of time on this portion, as it is just meant to be an activator and not necessary to understanding the core of the lesson at this time.
*Challenges and answer sheet courtesy of http://sciencespot.net/Pages/classforscistarters.html
Next, I pass out the Student Lip Print Lab and have the students read through the directions with their table groups. After the first reading, I would ask the students to paraphrase the procedures for both parts 1 and 2. Understandably, they will not be able to describe all of the steps in a way that is detailed enough to actually implement it. However, it will give them an overall idea of what is expected in this lab. We discuss the process, including how long the lab will take, what materials would be needed, etc.
Next, the students reread the lab, highlighting details that they will need to focus on when implementing the lab. I call on random students to share a few things they highlighted, asking the class to raise their hands if they also highlighted that specific step, sentence, or phrase. If a large number of students have their hands raised, this will signify to others that they should probably pay more focus to this specific part of the lab. We discuss this in quite depth, as the students will be responsible for understanding and following the procedures carefully without much guidance from me. Since I teach this unit later in the year after we have had many lab experiences, I feel students are at the point where they should be able to read and follow the directions written in a science lab. I have them grouped heterogeneously so that they can support each other, but I try to step away from reading or paraphrasing simple procedures and focusing more on posing clarifying or deeper level questions to groups of students as they perform labs. I feel this is a more useful way to facilitate discussion, reflection, and learning as students work in class.
Once students have read through the lab twice and highlighted the important ideas to keep in mind while performing the lab, I set them to work. As usual, I incorporate lab roles (from Ms. Sanchez's Class) to encourage students to both take accountability and work cooperatively during the lab activities. This provides structure to the classroom and ensures all students are involved in the learning tasks.
After completing the Day 2 portion of the lab, I have students jigsaw with members from other groups, forming new groups of 4 students. In these new groups, they each share the results of their Lipstick Chemical Analysis Data Sheet. They will compare the data they collected for accuracy. If they feel that they got very different results from another group, they will consult 2-3 people from other groups and compare to their results, so that they can determine which is the most accurate.
Once each group fees they have the most accurate data, they will work together (still in their new groups) to determine the suspect, based on the lip print and the type of lipstick that was used.
After students have finished, they may use Q-tips to collect some lipstick from the tube and place it on their lips to practice making and comparing their own lip prints to those of their teammates.
Students will easily be able to create and analyze their lip prints, but it is almost inevitable that someone will ask, "What if the suspect is a guy? They don't wear lipstick." To help them understand how to get lip prints from someone who may not wear lipstick, I play the Lip Prints video:
After watching the video, I ask students to consider what might be left behind if the suspect is not wearing lipstick or lip balm, as shown in the video. After giving some think time, I explain that lip prints can also be recorded by:
Hopefully, students will be able to draw upon the knowledge they have gained in the last few lessons and suggest that DNA from skin cells on the lip could be left on anything that the suspect has placed his/her mouth on. In this case, DNA can be compared to samples and analyzed to see if there is a match to a suspect or victim.
As a final evaluation of the lesson, I ask each student to use their laptop's webcam to record a verbal reflection that addresses the following questions:
They record their webcasts and send them to me via email. I will assess their understanding through the use of proper terminology, the accuracy of their responses, and the quality and comprehension of their responses.