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A Mini-Lesson


The Case of the Missing
Computer Chip

Mike McNabb (ENSI 89)
Tom Watts (ENSI 90)
Ruth Willey (ENSI 91)


Social Context

We now have a textbook for students on the nature of science. It's intended to replace, or supplement, the inadequate first chapter of your text. It's designed to coordinate and help sequence several of the nature of science (NOS) lessons on the ENSI site. It is targeted to students in any science class, grades 7-10 (or beyond). It helps to satisfy virtually all the new NOS standards in NGSS and Common Core. If you've used any of ENSI's NOS lessons, you already know how powerful they are. This new book addresses most of the common misconceptions about NOS. It also provides information about the differences between good science, poor science, and pseudoscience. It offers clues for recognizing those differences, and opportunities to practice using those clues. "What's this magic book I've been waiting for all my life?" It's called Science Surprises: Exploring the Nature of Science. "Tell me more - like where can I see this book?" Say no more. It's available as an eBook, published with Smashwords. Click Here to get more information and a link to sample (and purchase) the new eBook Science Surprises.


A simulated crime scene is presented for teams of students to solve, using clues received piecemeal, adjusting hypotheses as more clues are found and discussed. The elements of science are recognized through discussion of the crime solution metaphor. Also clearly shows how science is used effectively to reveal unwitnessed events of the past (by weighing the evidence), much as we do in paleontology, geology, evolution and astronomy.




1. Scientific knowledge is uncertain, tentative and subject to revision.

2. Scientific explanations and interpretations can neither be proven nor disproven with certainty.

3. Scientists use a variety of criteria to compare explanations and select the better ones.

4. Human values deeply influence science (its technology, the questions asked, and the criteria used for choosing among theories).

5. Scientific solutions to questions are generally collaborative.

6. Scientists look for more than one line of evidence to lead them to solutions. Independent lines of evidence pointing to the same solution provides compelling support for the solution.

7. Scientists attempt to integrate evidence into the larger framework of evidence which is already part of our knowledge base.

8. Evidence is not all of equal value.

9. Scientists look for ways to exclude some alternative solutions, thereby narrowing the focus on the one or few solutions which have the most and best supportive evidence.

10. Events of the past can leave clues which can help reveal the nature of those events.


Handout with introduction and procedures and map (one per team of 3-5)

Envelope (with 14 clues): one envelope per team


 (see end of lesson for the formatted handouts).

One handout sheet per team of 3-5:
- Introduction
- Procedures (you may prefer to eliminate these in lieu of your verbal announcemnts to go for next clues when you see they are ready)
- Map of Crime Scene (on back) [NEW MAP kindly provided by ENSIweb user Wendy Riggs]

Envelope with 14 clues on 14 strips of paper (one envelope per team)





Because this lesson provides an excellent opportunity to understand important elements of the Nature of Science , be sure to read our General Background Information, with our Rationale and our Approach, and tips for Presenting the lessons for maximum effect and Dispelling some of the popular myths about science.

In any of the discussions expected with the class, select a few key items (important concepts) that lend themselves to interpretation, and introduce class to the Think-Pair-Share (TPS) routine dealing with those items. This is how "Active Learning" is done.

This lesson can be done in a single 45' period, and is most appropriate in your introductory unit on the nature of science. It is similar to the "Checks" lab, the "Great Fossil Hunt" lesson, and others which involve the gradual influx of new data (new observations) to be considered in the solution of a problem. This is an important lesson to do as an historical scientific study, to compare with doing an experimental investigation. It can be used instead of or in addition to either of those lessons. It helps students to realize that there is no ONE "Scientific Method" for science.

The activity uses a simulation of a crime scene to help illustrate several principles of the nature of science. The participants are divided into groups of no less than three or more than five. Each team is then presented with an envelope containing: a) an introductory sheet b) a diagram of the crime scene, and c) 14 clues.

After reading the introductory sheet and looking at the diagram, each team draws five of the clues from the envelope, at random. Using the information at hand they attempt to solve the crime by organizing the evidence in various ways that may lead them to a tentative explanation.

After a team feels they have exhausted their ideas with these clues, more evidence can be uncovered. Each team may then draw three more clues and begins the process anew. Observe groups for insights as to how the new information affects their old predictions. Once again, allow each group to work until they have exhausted their individual lines of thought, but do not discourage minority opinions.

Each team should then draw three more cards and proceed as before, but after a few moments groups should be encouraged to collaborate. After a time allow them to draw the final three clues and continue until there is some general agreement, always allowing for minority opinions.

Discussion This exercise is designed to help explain the idea that science is built on evidence that can be observed or deduced from the physical world. This exercise helps explain the concept that it is the nature of science to explain events as having natural causes. This evidence is often confusing, seemingly conflicting, and apparently random. Scientists, then, hope to be able to find more than one line of evidence to help them solve a problem. They would like to integrate this evidence into the larger framework of evidence that is already part of the knowledge base and make connections in new and different ways that may allow new and different ways of looking at a problem.

In the game there are several independent types of clues that may be used to develop a solution. This component of the game is used to illustrate the concept that scientists use a variety of criteria to compare explanations and select the better ones. This is one of the major objectives of the exercise. Another important aspect of science is the ability to connect disparate lines of evidence to form a new hypothesis. Hopefully, the game players will see that with new evidence comes new ways of connecting the clues. If not, point it out. Also, evidence in science, and in this simulation is not all of equal value. In the simulation, the value of each clue is affected by the order in which it comes, and by the relative importance placed upon it by the various group members. Individuals with strongly held opinions or with strong personalities may have a major effect on the currently held opinions, even though their reasoning may not be clear. This aspect of the game best illustrates that human values deeply influence science, its terminology, the questions asked, and the criteria used for choosing among hypotheses. Good science must also provide ways to exclude some alternatives for the larger universe of possible solutions. This may be illustrated by the combination of clues that seem to remove certain characters from suspicion, e.g. lack of motive, opportunity, etc.

Another important aspect of the game is that it is open ended. There is not enough information presented to say with certainty who the thief is and each clue may often create more questions than it helps answer. This is a dynamic aspect of both the game and science. For that reason, there is NO KEY. Just as in science, our best understanding of nature comes from critical thinking and analysis of the best evidence.

An aspect of science not often presented is its capability of revealing non-witnessed events of the past, based on an analysis of observed clues found in the present. This is "historical science" as opposed to "experimental science." Ask students to name science fiields where this process of science is more typical than experimental processes. These "historical sciences", include paleontology, geology, evolution science, forensic science and astronomy; they all fit into this form of investigation. These are not traditionally "experimental" sciences, as such, in which events are repeatable, but, as crime scene simulations reveal, this brand of science is every bit as useful for understanding the natural world. Instead of predicting a likely outcome of an experiment (based on the tentative explanation), in historical scicnces, scientists predict what they should observe if they look in the right place, or in the right way, based on the tentative explanation.

Finally, this is a simulation that encourages participants to equate the solving of the crime and seeking of justice with the search for scientific reality. Good science, just as good law, must be integrated into a larger cognitive framework.

THE 14 CLUES: On separate sheet (see PDF versions at end of lesson). Make enough copies so that there will be one set per team. For each set, cut the clues apart, mix them up, and put them in an envelope. Repeat for each set. The 14 clues are also listed below for convenience.


Doug, the man who operates the coffee cart in the parking lot (see map) reports that he has not seen any strangers today. In fact, this is what he reports: "I saw the security guard arrive at 7:00 for the shift change, same time as Cowboy Paul's delivery truck. The security guards came out playing with those night sticks and the Cowboy was listening to that 'Hillbilly' music on his headphones, when they came out for a cup of coffee."

According to Coffee Cart Doug, the lab assistant, Ginny, "arrived at 7:15, turned the lights on in the office for about 5 minutes, just like always. And then about 7:50, the lights came on and I could see Ginny working in the lab."

Coffee Cart Doug reports: "About 7:30, the lights came on again in the lab for about 5 minutes. They have those motion sensor lights, you know."

Coffee Cart Doug reports: "Then at 8:00 the loading crew arrived and started unloading Cowboy Paul's delivery truck."

Coffee Cart Doug reports: "Nobody else came or left till Randak arrived at 8:50 which was actually early for him. Couple minutes later the police arrived."

Ginny reports: "I got to work at the usual time and opened the office just before 8:00. Nothing unusual happened."

Security Guard Jim's statement: "My shift starts at 7:00; I had a cup of coffee with Cowboy Paul and Buck, the night guy; then I did my rounds and found everything was secure."

Cowboy Paul's statement: "I arrived about 7:00 a.m., had coffee with the security guards and waited for the loading crew to unload my trailer. I was just about to leave when the alarm went off and I got locked in. "

MOTIVE: Cowboy Paul: Seems to live beyond his means according to security guard; drives Porsche and wears Rolex watch. Owns three Kentucky thoroughbred race horses. But he still loves Levis. He needs money.

MOTIVE: Security Guard Jim: 'Hacker'; wants to be the first on his block to have new stuff.

MOTIVE : Ginny Fletcher: Actually developed algorithm for this computer chip and has received no financial or professional recognition for her contribution. She feels shortchanged.

EVIDENCE: Fingerprints: In the lab a single partially smudged print was found and since all employees have prints on file, it was easily ascertained it belonged to persons unknown.

EVIDENCE: Fiber Evidence: A small thread that was later identified by the police as denim was found by Randak when he microscopically examined the chip to verify it as his missing chip. Also found were small white crystals of sugar.

EVIDENCE: Misc. Evidence: The door to the private lab is secured by a tone lock. Known access is limited to president and assistant.


 Try another "Crime Scene" scenario with our new lesson: "A Crime Against Plants."

Try a new "forensic" style lesson on this site: "Mystery of the Matching Marks" that takes students on a problem-solving quest to test the hypothesis that our long #2 chromosome was formed from the fusion of two shorter chromosomes found in chimps today. Students search for the molecular fossils (telomere DNA) in the middle of their #2 chromosome. This would be most appropriate following your study of chromosomal inheritance.

Look into the new standards-based curriculum units and lessons on forensic science for middle and high school students, developed and made available FREE by NSTA and Court TV: "Forensics in the Classroom". Lessons are appropriate for biology, chemistry and physics classes. (Posted 22 October 2003.

OTHER RESOURCES (posted January, 2016):
Search: "crime scene investigations for classroom"
Or search for "forensic science for classroom"
Go to Reddy's Forensic Page
Or Nancy Clark's Forensic Page


Some of the ideas in this lesson may have been adapted from earlier, unacknowledged sources without our knowledge. If the reader believes this to be the case, please let us know, and appropriate corrections will be made. Thanks.

1. Original Source: Mike McNabb (ENSI 89), Tom Watts (ENSI 90), and Ruth "Babe" Willey (ENSI 91).

2. Reviewed / Edited by: Martin Nickels, Craig Nelson, Jean Beard: 12/15/97

3. Edited / Revised for website by L. Flammer 5/99

4. NEW MAP kindly provided by ENSIweb user Wendy Riggs, July 2011.


 The following is the student handout (Introduction and Instructions). Also available in PDF format (see below).




It's the morning of July 5 in the northern California city of Cupertino. You are working the burglary watch, day shift. As commander of the electronic theft division you have a team of experts, skilled in the collection of all types of evidence relating to theft of computers and electronic stuff. At 9:50 a.m. you get a call that someone has attempted to steal an advanced chip from the Plum Computer Company. You and your team respond immediately to the call. When you arrive, you find that the plant is sealed off and all the uniformed employees in the plant have been confined to a single room, the lounge. Within the hour, the missing chip is found in an envelope in a pile of mail. The envelope was addressed to Gordon Lidy, the security chief of a rival computer firm. A cassette tape was also found in the envelope.

You assign one of your best officers, JoAnn Lane, to interview everyone present. Here is what she finds:

A. Steve Randak, the president, arrived at 8:50 this a.m. to find the tone-operated security door to his private lab open and the prototype of his new computer chip missing. He immediately pushed the panic button that alerts security to close the gates. The guard at the gate reported that no person had left the plant since 8:00 a.m. today.

B. A map of the crime scene

C. Jo Ann begins accumulating clues, and as she does, tries to develop a hypothesis for how it was done, and who did it. She keeps her clues in an envelope.


INSTRUCTIONS for each team:

1. Read the Introduction (above)

2. Study the map of the crime scene (overpage)

3. After reading the above introduction and studying the map of the crime scene, your team should draw 5 (five) clues at random from the envelope.

4. Using the information at hand, try to solve the crime. You can organize the evidence in various ways, until your team develops a tentative hypothesis. Do not discourage minority opinions. Commit yourselves by writing down this hypothesis.

5. Once you have exhausted all your ideas with these clues, more evidence can be uncovered. Your team may now draw 3 (three) more clues from the envelope, at random. Repeat step 4.

6. After a few minutes, get together with another team or two...collaborate...compare clues, compare notes, compare ideas. See if you can reach a better hypothesis collaboratively.

7. Draw the last 3 clues, and continue as before until there is some general agreement, always allowing for minority opinions. Record your final team consensus...your hypothesis for what happened, and who was probably responsible. Be able to defend your hypothesis.

8. When all teams have pretty well arrived at some "final" hypothesis, you will be asked by your teacher to participate in a class-wide discussion in which you can share hypotheses and the rationales for arriving at those hypotheses. You will be asked to critique each other's hypotheses and reasoning. Hopefully, you may be able to arrive at a class-wide general consensus.

9. In any case, you will also be asked to analyze your activites in trying to solve this crime. What elements were at work which are also found in the process of SCIENCE?



Crime Scene (2 pages): Teacher Notes and Clues

Crime Scene (1 page): Student Handout

Crime Scene (1 page): Crime Scene Map
[NEW MAP kindly provided by ENSIweb user Wendy Riggs]


 These pages are in Adobe Acrobat pdf format in order to maintain their intended layout for easy printing of handouts. Only a "thumbnail" reduced size image of the first page is showing (if more than one page is in that file). For enlarging and copying, (and seeing other pages in that file), you will need to download the free Acrobat Reader from Adobe (unless it's already installed in your system). Then just click on the blue file name above, below, or next to the first page. You may see the "Acrobat Exchange" (Reader application) loading, then the pages will display. You might need to shift-click and drag the lower left corner of the page to enlarge it, or click the magnifying glass on the menu bar.

If this doesn't seem to work, you might need to load and/or enable the PDFViewer plug-in by following one of these protocols:

For Netscape Communicator: EDIT>Preferences>Navigator>Applications (then scroll down to "Portable Document Format (PDFViewer)", click on it, then click OK; if it's not there, click on "New", and add it in).

For Netscape Navigator: OPTIONS>General Preferences>Helpers (scroll to check for PDF on list, add it if it isn't, then click OK to activate it.

For other browsers, or problems with this, check with your browser tech support, Adobe tech support, or, in dire frustration, contact THE WEBMASTER If nothing else, I will mail you hard copy of the formatted pages desired.

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