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 Hunt for the Serial Arsonist Ideas from Teachers

(Gr. 6-8)
Objective
To classify fingerprints into one of three main catgegories—loop, whorl, or arch—and then demonstrate understanding of Galton characteristics by using the characteristics to identify and match fingerprints of classmates.

Materials

• copy of Mathematics, Engineering, and Science Achievement (MESA) "Classifying Fingerprints" by Nancy Cook (optional)
• copy of three main types of fingerprints—loop, whorl, arch (in "Classifying Fingerprints"); if you don't have the book, search online for pictures of the three types of fingerprints
• enlarged copy of prints that display the various characteristics (delta, bifurcation, dot, ending ridge, etc.)
• copy of the Galton characteristics (in "Classyifying Fingerprints"); if you don't have the book, search online for "Galton characteristics")
• 3 x 5 index cards (preferrably white and unlined)
• 6-8 rolls of clear tape (1-inch wide)
• No. 2 pencil (1 per student)
• handheld magnifying glass for each student
• bucket of soapy water and paper towels
• scissors (for tape dispensers that don't tear tape properly)

Procedure

1. Introduce the topic of fingerprinting and explain why it is an important tool used by forensic experts. Explain that it takes a college education to become a forensics expert and that such people use science to help solve crimes.

2. Give students copies of background information on the history of fingerprinting. If you have a copy of "Classifying Fingerprints" then you'll have the appropriate student handouts in that book. Otherwise, you can make your own by searching online for that topic. Give students a copy of the three main types of fingerprints and enlarged copies of real prints that fit each category.

3. After teaching students about Sir Francis Galton (in information from online search of the history of fingerprinting) and the characteristic fingerprint markers that he identified, give students a copy of those markers. Enlarge some fingerprints and put each on a transparency. Help students identify the Galton characteristics on these prints. Each students should have an enlarged copy of the prints featured on the transparency.

4. When students are comfortable identifying the three main types of prints and the Galton characteristics, then they are ready to make a print of their right index finger. Give each student several 3 x 5 cards (they might need more cards in case they mess up). In the middle of one of the cards, students use a No. 2 pencil to make a graphite rubbing measuring about 2 x 2 inches.

5. Working in pairs, have students take turns getting graphite on their right index fingertip (completely cover sides and middle part of fingertip). Student A holds a piece of clear tape (sticky side up) for Student B. Student B rolls his/her fingertip from left to right (or right to left) and then lifts up fingertip (they should not roll back over print). Student A lifts up tape and presses the sticky side down onto the card. Student B puts his/her name on the back of the card. Then, the procedure is repeated but no name is put on the back of the card. Student brings both cards to the teacher who puts a code on the back of the second card, so that the teacher can identify to which student the card with no name belongs. Now, Student B holds the tape for student A and he or she makes a set of two cards--one with his/her name on back and one with a code on the back.

6. When the entire class has finished this task and the teacher has coded all of the cards with no name, then students are ready to do the matching assignment. Provide each student with a magnifying glass. Cards with names on the back are taped down onto a large table (or tables). Students are then randomly given a print (with code on back). They are told to use their forensic skills to match the card they were given to one of them on the table.

7. When all cards have been matched, verify that the matches are correct or not.

8. Then, ask students to classify the prints into the three main types--whorls, loops, arches. Have those categories listed on a large dry erase board. Students remove the set of prints they matched and put that pair of prints in the correct category.

9. Extend this activity into mathematics by having students determine the percentage of class prints that were in each of the three categories. Ask how this compares to the percentage of those types in the general population. Is the class data similar to general population data? How does size of the data sample affect the results? Graph the occurrence of each category of print in the class.

10. Students can extend their learning into language arts by writing an expository essay on the history of fingerprinting and how computer technology has changed how fingerprint data is stored, accessed and shared with law enforcement officers all over the world.

Assessment
The activity itself is a formative assessment. I also made a traditional paper and pencil test that included true and false as well as fill-in-the-blank type questions (with word bank at bottom of page).

Example:

Classifying Fingerprints Quiz

True or False

1. Evidence indicates that fingerprints have been used for over three thousand years to seal documents, or in place of a signature. (Answer: True)

2. The three main types of fingerprint categories are ovals, spirals and waves. (Answer: False)

3. Sir Francis Galton identified certain characteristics that occur in some prints, but not in others. (Answer: True)

4. Forensic experts "lift" latent prints from a surface by dusting the prints with a fine powder that adheres to the oil from skin. (Answer: True)

5. A college degree isn't necessary to become a forensic scientist. (Answer: False)

Fill in the blank

1. A _________ is one of the Dalton characteristics and is shaped like a small triangle. (Answer: delta)

2. A _________ is another Dalton characteristic and is shaped like a Y. (Answer: bifurcation)

3. A _________ is one of the three types of fingerprints and it's shaped like a spiral.

4. Forensic scientists use a special type of light called a _________ to find latent prints. (Answer: laser)

5. Computers use a _________ number system to classify, sort and identify fingerprints. (Answer: binary)

Classroom Tips

1. Have all materials ready and in a central location.

2. Ask for student volunteers to give out and collect materials.

3. Give students a binder or folder in which to keep materials.

4. Store binders or folders in the same place every day and have students put them in that place at the end of class.

5. Praise students often and let them hear you "brag" about their expertise as forensic scientists.

6. Reward students with a visit from your local police department officer who'll show them how to lift prints, etc.

Sent in by
Barb Przasnyski
Woodbrook Middle School
Lakewood, WA

 Hunt for the Serial Arsonist Original broadcast:November 14, 1995

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