Chemistry Everyday for Everyone
Engaging Students in the Action of Chemistry An Effective, Fun, and Inexpensive Outreach Program Jane M. Van Doren and Lisa P. Nestor Department of Chemistry, College of the Holy Cross, Worcester, MA 01610-2395 W. Berk Knighton Department of Chemistry, Montana State University, Bozeman, MT 59717 Engaging students actively is essential for an effective outreach program. Many such programs have been described in this Journal and elsewhere (1–8). Because of the prominence of forensic investigations in the media, we developed a mystery for our outreach program, which students solve through a combination of chemical experiments and critical thinking. We designed our program for middle school students with little or no laboratory experience. To date, we have involved three groups with 10–15 students in each group. Two of the groups have been part of Holy Cross College’s week-long vacation camp program called the Youth Exploring Science Program, which is sponsored by the Howard Hughes Foundation. The mystery begins with a theatrical presentation of the problem at hand: Ethel (see mystery below) comes running into the classroom displaying great distress at the theft of the valuable painting and the premature departure of the police. She pleads with the students to identify the evidence and find the thief, handing each student a packet of information and each pair of students a detective kit. The information packet includes a synopsis of the mystery, a list of evidence, information about the suspects, structured experiment sheets, and hints on how to organize their data and solve the mystery. The detective kit includes small samples of the 6 pieces of evidence, personal safety equipment (lab glasses, aprons, gloves), lab marking pens, and name tags. The Mystery Great uncle Aaron Krysnofsky recently died. In his will, he left his grand nephew Albert a wonderful original painting by Van Gogh, the famous “Starry Night”. Albert and his
wife Ethel hung the masterpiece above the fireplace in their enormous living room. It looked wonderful and really spruced up their dreary mansion. In celebration of this new acquisition Albert and Ethel decided to hold a grand party. They invited many guests, including Randy the Rare Finds Art Dealer, Larry the family lawyer, and Albert’s cousin Freda. Because the affair was going to be large, they hired an outside agency (“Flamingos and Feasts”) to serve the food and to clean up. Their own personal cook, Clarice, and the head caterer, Francine, prepared all of the food. Ben, their butler, greeted guests, took care of their coats, cleaned up their messes, and showed them around the mansion. The party began with food and drinks served to the guests in the living room so that everyone could admire the painting. Everyone had a good time, except the woman whose very expensive shoes were ruined when the bathroom sink clogged! Ben efficiently cleaned up the mess and ¯ unclogged the sink (using Dr ano, which is kept under the kitchen sink). After about an hour all the guests went into the parlor for a bit of classical music played by the hired quartet. At the conclusion of the performance everyone returned to the living room for coffee and tea but the painting was gone! Albert spotted a small white paper on the coffee table but in his anger, ripped it to shreds. Ben quickly called the police and asked all the guests (and hired help) to stay for questioning. The police came immediately, collected evidence, and searched everyone. Unfortunately, they were called away on a more important case before they could complete their investigation. They have turned the case over to you. Identify the various pieces of evidence and find the thief! Good luck!
Table 1. Information and Materials Provided
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Evidence
Possible Identification
Defining Reagent
Result
Clumpy white powder
plaster of Paris, cornstarch
tincture of iodine
plaster of Paris turns brown; cornstarch turns blue
White crystals
NaOH & Cu(NO3)2 or Cu-reducing tablets
Clear liquid
fructose, sucrose, salt Dra¯ no, water
fructose turns red; sucrose turns deep blue; salt has no reaction "Dra¯ no" turns pink; water has no reaction
Fine white powder
powdered sugar, baking soda
vinegar
powdered sugar has no reaction; baking soda bubbles
Metal shavings
aluminum, steel
magnet
steel is magnetic; aluminum is not magnetic
A piece of the ransom note
various black felt-tip pens
water (paper chromatography)
each pen produces a unique chromatogram
Ex-Lax tablets; (phenolphthalein)
Journal of Chemical Education • Vol. 74 No. 10 October 1997
Chemistry Everyday for Everyone Concluding Remarks
Table 2. Data Analysis Table Evidence
Suspect Randy
Larry
Freda
Clarice Francine
A = plaster of Paris no info no info no info no info no info B = fructose
–
C = Dra¯ no
no info no info no info no info no info
+
–
+
+
D = baking soda
–
–
–
+
+
E = steel
+
–
+
+
–
F = Paper❤❤ Mate
–
+
+
+
–
The Evidence Unraveled: Laboratory Experiments Students were given a brief description of the evidence collected, relevant information about the food and drink served at the party, and important details of the mansion floor plan. In order to keep the program to two hours, we narrowed the identity of each piece of evidence to 2–4 possible substances (see Table 1). The student detectives were provided with authentic samples of each of the possible substances, limited reagents with which to test samples, lots of empty sample vials with caps, plastic pipets, and spatulas. The defining reagents are listed in Table 1. Within this structured environment, the detectives were allowed to design and carry out experiments of their choice. When they devised an experiment that could distinguish between the possible substances, they tested their evidence. To encourage the students to completely develop their analytical method/test and to demonstrate that definitive results can be obtained on small samples, the evidence samples given to students were extremely small. Finally, students were required to make a written record of the tests performed, their observations, and their conclusions concerning the identify of each piece of evidence. Solving the Mystery: An Exercise in Critical Thinking After their analysis was complete, the student detectives adjourned to the discussion room to solve the mystery. For our limited time frame, we minimized extraneous information. Students were given suspect names, motives, food and drink preferences, and objects found in their possession. To help them organize and interpret the data, we encouraged them to make use of the grid shown in Table 2. By consulting the suspect information, story synopsis, and their identification of the evidence, the detectives determined whether a suspect was implicated or eliminated by the evidence. Some evidence did neither. When the detectives believed they could identify the thief, they handed in their “Solution” and were given a sealed envelope with the thief ’s name inside. For fun, the name was written with invisible ink (lemon juice), which they then developed in a dilute iodine solution. All students were able to successfully identify the thief (Clarice).
In this mystery, there is no misleading evidence, as there might be in a real forensic investigation; that is, the suspect with access to all the different types of evidence found at the scene is the thief. However, no single piece of evidence identifies the thief and some evidence provides no information as to the identity of the thief. This combination provided the students with a challenge in analytical reasoning. Our students initially put emphasis on positive results only and were unsure what to do with “no information” evidence. With some assistance, they worked through these problems and were able to solve the mystery. Our program’s goals are to spark interest in science and to build student self-confidence by actively involving them in an experimental investigation. The program is designed to be simple enough that students can be the “principal investigators” (be in charge of all aspects of the investigation), yet interesting and challenging enough to keep their attention. The evidence and chemical tests were chosen to involve substances familiar to the students, which they could handle with minimal safety issues. In addition, the materials used are relatively inexpensive and can be purchased in supermarkets or pharmacies. Through this investigation, students with little or no laboratory experience learn about experimental design, careful observation, and analytical reasoning, and they have fun in the process. Copies of the student and instructor lab packets are available upon request. Acknowledgments We wish to thank and acknowledge the numerous Holy Cross chemistry students, lab supervisors, and faculty who have taken part in this program and made it a success. We also acknowledge and thank the Howard Hughes Foundation for supporting the YES program at the College of the Holy Cross, thus making it possible for students to participate in our program. J. M. V. D. acknowledges support from the Camille and Henry Dreyfus Foundation, Inc. Literature Cited 1. Borgford, C. L.; Summerlin, L. R. Chemical Activities: Teachers Edition; American Chemical Society: Washington, DC, 1988. 2. Grosser, A. E. The Cookbook Decoder, Beaufort: New York, 1981. 3. Heinze, K. F.; Allen, J. L.; Jacobson, E. N. J. Chem. Educ. 1995, 72, 167. 4. Hermens, R. A. J. Chem. Educ. 1995, 72, 165. 5. Rybolt, T. R.; Waddell, T. G. J. Chem. Educ. 1995, 72, 1090, and references cited therein. 6. Solomon, S.; Fulep-Poszmik, A.; Lee, A. J. Chem. Educ. 1991, 68, 328. 7. Tracy, H. J.; Collins, C.; Langevin, P. J. Chem. Educ. 1995, 72, 1111. 8. VanCleave, J. P. Chemistry for Every Kid; Wiley: New York, 1989.
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