SUCCEED

Fingerprints

Objective: Students will learn about forensic analysis by dusting for fingerprints and using a graphics program to match the fingerprints found to existing ink prints.

This lesson is composed of two sections:

• Dusting for Fingerprints
• Fingerprint Analysis Using GIMP

Materials: Each student will need

• A pair of plastic disposable gloves
• A piece of newspaper
• A light colored object (drinking glass, mirror, yellow or orange plastic)
• The tools needed to dust for fingerprints: Lightning powder, a fingerprint brush, and a roll of scotch tape
• An index card to hold their completed fingerprints
• Baby wipes
• A computer with GIMP and two fingerprints saved on the desktop.

Explorations questions for students:

1. What are the different types of evidence found at crime scenes?
2. How do scientists go about analyzing this evidence?

Introduction to Fingerprints:

1. Introduce students to the characteristics of fingerprints and why fingerprinting works
2. Allow students to look at their own fingerprint and determine its characteristics.

Dusting for Fingerprints

1. Demonstrate the process.
1. Wear gloves.
2. Shake the jar of powder back and forth before you open it to make it level.
3. Open the jar and put the lid right next to it.
4. Put the brush on top of the powder straight up and down so that it barely touches it.
5. Hold the brush over the lid of the jar sideways and tap off the excess dust.
6. Brush the powder onto the object by twisting the brush over it with your thumb and forefinger.
7. A print should appear.
8. If you have tons of excess powder, you can brush it off using the brush. Do not worry about wiping off the powder on the fingerprint, you will not.
9. Put the brush down and get a piece of tape. The best way to do it is hold it with two fingers on one side and pull it long enough so that you can hold it with two fingers on the other side and your fingers will not overlap the actual print
10. You do not need to press the tape down onto the print. This may cause air bubbles, which we do not want.
11. Peel back the tape carefully so that it picks up everything.
12. Place the tape onto an index card, but do not touch the part with the print.
13. Pick up the lid of the jar and pour the extra dust back in.
2. Let students work alone or in groups and dust for their own fingerprints on a glass or object.
3. If any group can do this well, let them dust an object from the crime scene and save the fingerprint for analysis.
4. Lead the students in cleaning up their working space.
• Wipe off the objects and the table with a dry paper towel, then with a baby wipe.
• Knock the extra powder from the brushes before putting them away.
• Fold the newspaper from the corners to prevent the powder from spilling out, then throw it away.
• Throw away the gloves.

Fingerprint Analysis using GIMP

1. This activity can be done by the students on their computers or by the teacher with the students giving suggestions on what to do next.
   1. Open the first fingerprint twice and the second fingerprint once using GIMP.
   2. Create two new layers inside the first fingerprints document.
   3. Cut-paste the duplicate of the first fingerprint onto a layer in the first fingerprint.
   4. Do the same for the second fingerprint.
   5. Use the select and move tools to position the second fingerprint on top of the first fingerprint within its layer.
   6. Change the opacity on the layer containing the second fingerprint so that the first fingerprint is visible underneath it.
   7. Continue resizing and manipulating the second fingerprint until you are able to compare the lines on the first and second prints and determine if they came from the same person