This investigative case module was prepared as part of a BioQUEST faculty development workshop entitled PRISM Workshop: Implementing Investigative Case-Based Learning at Center for Science Education in June 2003. The cases, resources, and implementation strategies were developed by participants for use with their own students. We invite you to adopt and adapt the following materials.

The BioQUEST Curriculum Consortium is committed to the reform of undergraduate biology instruction through an emphasis on engaging students in realistic scientific practices. This approach is sometimes characterized as an inquiry driven approach and is captured in BioQUEST's three P's (problem-posing, problem-solving, and peer-persuasion). As part of this workshop groups of faculty were encouraged to initiate innovative curricular projects. We are sharing these works in progress in the hope that they will stimulate further exploration, collaboration and development. Please see the following links for additional information:

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Investigative Cases
   
The Case: Signed with a Kiss

Begin Scene One

Before third period, Marie goes to her locker to grab her chemistry book. She and Christopher have shared this locker for the last semester when they started going together. It was a natural attraction since Marie is the dance squad captain and Christopher is the quarterback of the varsity football team.

As Marie rushes to get to her desk before the bell rings, her lab partner Mark says gesturing to the book in her hand, “Marie, so you’re back in geometry, huh?” She sighs, “I can’t believe I grabbed Christopher’s geometry book instead of my chem book!” Mark smiles and says, “Don’t worry, we can share mine.” Marie and Mark have been friends since middle school, now they see each other in several classes during the day and after school at track practice. Mark has always been a hard worker in class as well as on the track. Currently, he is the state champion in the 100m dash, the starting running back for the varsity football team, and president of the beta club and the chem club.

End Scene One

Begin Scene Two

As she pushes Christopher’s geometry books aside, it falls to the floor and a note falls out. Marie leans over to pick up the note, she notices the swirly handwriting. “This is interesting…” Marie says as she realizes the handwriting is not hers. She and Mark scan the note…


“…can’t wait to see you again, baby. Last nite was so much fun! Call me on my cell after school today.”


Marie was already bugged out by the words of the note, but on top of that, the girl had the nerve to sign the note with nothing but a kiss!

End Scene Two

Begin Scene Three

After school, Marie calls Mark for support. Between sobs, Marie explains to Mark, “I was so cold to Christopher after Chem class. I’m afraid he thinks I know about the note.” Mark reassures her, “Naw, he has no idea. I saw him today after sixth period. He has no clue, I think he would have said something to me.” “Okay,” she says, “let’s continue with our plan.”

She lists some of the girls she thinks could have sent the note to Christopher. “You know that little cheerleader, Debbie, has always liked him. She and I aren’t even friends so I’m sure she’d have no problem sneakin’ around with my guy.”

Mark agrees, “I’ve seen her talking to Christopher after football games. He never seemed very interested in her, though.” Mark continues, “You know who else was always around after football games, the team manager Leah!”

“He talks about her all the time!” says Marie with exasperation.

“That’s because she’s always jocking him,” laughs Mark, “But she’s always jocking the whole team!”

Marie sucks her teeth and snaps, “I don’t really wanna think about that!”

“I know, I was just kiddin’ Marie! C’mon, don’t you want to know who it is? Let’s get this plan together!”

“Okay Mark,” says Marie, “I really can’t think of anyone else, can you?”

“Well…,” He says with hesitation, “You may not want to hear this, but yesterday after school, I saw your girl Muhsinah walking with Christopher behind the band room.”

“Oh please! Muhsinah is my best friend! She’s not that scandalous.” argues Marie, “Plus, she was at a play with her cousin last night.”

Mark gives up, “If you say so. Just make sure you get a sample from each of those girls. Oh yeah, and make sure that you have plenty of nail polish remover. I think that will be the best solvent to separate the mixtures. When I come over tomorrow, I’ll bring the coffee filters.”

End Scene Three

Begin Scene Four

The next day, Marie and Mark meet up at her house to begin the investigation phase of their plan. Mark says, “How did you get all three of these girls to give you their lipstick?”

“Oh man, have you ever been in a girls’ bathroom at high school?” Marie teases.

Mark grins, “NO!”

“Well, we are always sharing beauty secrets…all I had to do was compliment them on how beautiful their shade was and, they told me the brand.”

“If they only knew!” exclaims Mark!


Begin lipstick chromatography lab.

End Scene Four

Epilogue

After discovering that Christopher and her girl Muhsinah were not the friends she thought they were, Marie confronted them with the evidence. Christopher and Muhsinah were shocked at her use of chemistry to catch them. Marie recovered from the nasty breakup with Christopher with the help of Mark's comforting shoulder... ;)

Case Author:
Ken Townsel
Stephanie May Stephenson High School
Doris Goodley
Leah Anderson Emory University:Center for Science Education
Muhsinah Holmes

Case Analysis

Option: Include a know / need to know chart like the one below:

What do you know?
What do you need to know?
   

Learning Goals

Goal(s)

The student will be able to:
a) identify the characteristics of a substance, b) utilize paper chromatography as a method of separating mixtures, c) contrast mixtures and substances, d) classify mixtures as homogeneous or heterogeneous, e) calculate the Rf factor for each component of a mixture separated on a chromatograph.

Areas of Knowledge.
Principles of chromatograpy.
Solvent properties.
Techniques for separation of mixtures.
Properties of compounds.
Manipulation of measurement tools.
Scientific process skills.
Development of concept map.
Laboratory safety procedures.

Standards

Georgia Standards and Quality Core Curriculum (QCC) Objectives

Standard 1. Uses scientific process skills in laboratory or field investigations, including observation, classification, communication, metric measurement, prediction, inference, collecting and analyzing data.
QCC 1.1 Designs and conducts a scientific experiment that identifies the problem, distinguishes manipulated, responding and controlled variables, collects, analyzes and communicates data, and makes valid inferences and conclusions.
QCC 1.2 Evaluates procedures, data and conclusions to determine the scientific validity of research.

Standard 2. Uses traditional reference materials to explore background and historical information regarding a scientific concept.
QCC 2.1 Uses current technologies such as CD-ROM, Internet and on-line data search to explore current research related to a science concept.

Standard 3. Learns and uses on a regular basis standard safety practices for laboratory or field investigations.
QCC 3.1 Learns and uses safety procedures specific to an investigation or research activity.

Standard 16. Given a mixture of liquids and/or solids, classifies the mixture as: homogeneous, heterogeneous, miscible, immiscible, or a colloid.
QCC 16.2 Identifies factors that affect solubility of a substance and theories that explain the formation of solutions.

 

Investigations and Activities

Lipstick Chromatography Lab Protocol

Materials:
Chromatography paper or Coffee filters
Scissors
3 different Lipsticks similar in shade, but different brands
Acetone or Nail Polish remover with Acetone
Beaker or Cup large enough for 3 strips of paper (about 500 ml)
Tape

Procedure:
1. The teacher has smeared samples of the lipstick from the note and each of the suspects onto filter paper. Each group will analyze one suspect or the sample from the note 3 times.
2. Carefully pour 10 ml of solvent into the beaker.
3. Place all three strips of paper into the beaker so that the paper touches the solvent, but that the level of the solvent does NOT reach the lipstick.
4. Secure the top of each paper strip to the beaker with tape if necessary to keep it from slipping.
5. After 15 minutes remove all the samples from the beaker and place the papers flat on the bench top.
6. Measure the distance the acetone traveled up each strip of paper. Also measure the distance each component moved up the paper.
7. Make a data table with average Rf value for each component in your lipstick sample.





 

Resources

Students will usually obtain additional references or resources
to help answer or explore their questions.

Special Data Items

Evidence: The note to Christopher with lipstick kiss

1. paperchromatograph.jpg
2. Rfformula.jpg
3. lipstickkiss.jpg

 

Student Products

Assessment and Evaluation Plan

*After the conclusion of the case, students will write another problem teaching the same concepts. For example, they should be able to identify another mixture that could be separated/identified by chromatography. The students cases will then be evaluated by the whole class (anonymously) as to how well the new cases meet the objectives.
*Each group will write a magazine article teaching others how to "do it yourself" using chromatography to "Catch their man cheating!"
*Students will recreate the lesson plan (including objectives) for this case.

 

Implementation

Course name:
General Chemistry, Accelerated Chemistry
Likely sequence in syllabus:
After basic introduction to elements, compounds and mixtures
Time during term:
Duration:
2-3 days
Setting:
Classroom, laboratory, library
Students in course:
20-30 students per class period
Collaborative elements:
Additional notes:

 

Credits

This scene and laboratory protocol were adapted from, "Who's Lipstick?" in Crime Scene Investigations by Pam Walker and Elaine Wood, 1998.

The images of the paper chromatograph and lipstick kiss where found at http://www.ausetute.com.au/chromato.html and http://www.consumerreports.com, respectively.

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