T. Trimpe 2006

Transcription

1 T. Trimpe

2 Fingerprint Principles According to criminal investigators, fingerprints follow 3 fundamental principles: A fingerprint is an individual characteristic; no two people have been found with the exact same fingerprint pattern. A fingerprint pattern will remain unchanged for the life of an individual; however, the print itself may change due to permanent scars and skin diseases. Fingerprints have general characteristic ridge patterns that allow them to be systematically identified.

3 Fingerprint Classes There are 3 specific classes for all fingerprints based upon their visual pattern: arches, loops, and whorls. Each group is divided into smaller groups as seen in the lists below. Arch Plain arch Tented arch Loop Radial Loop Ulnar loop Whorl Plain whorl Central pocket whorl Double loop whorl Accidentical

4 Interesting Info Fingerprint Factoid: 60% of people have loops, 35% have whorls, and 5% have arches Did you know? Dactyloscopy is the study of fingerprint identification. Police investigators are experts in collecting dactylograms, otherwise known as fingerprints.

5 Arches Arches are the simplest type of fingerprints that are formed by ridges that enter on one side of the print and exit on the other. No deltas are present. Spike or tent Plain Arch Ridges enter on one side and exit on the other side. Tented Arches Similar to the plain arch, but has a spike in the center.

6 Loops Left Hand Loops must have one delta and one or more ridges that enter and leave on the same side. These patterns are named for their positions related to the radius and ulna bones, i.e. the bone the loop opening is facing towards. Ulna Radius Delta L Radial Loop R - Ulnar Loop L Ulnar Loop R - Radial Loop X-Ray Imagine:

7 Whorls Whorls have at least one ridge that makes (or tends to make) a complete circuit. They also have at least two deltas. If a print has more than two deltas, it is most likely an accidental. Plain Whorl Central Pocket Whorl Draw a line between the two deltas in the plain and central pocket whorls. If some of the curved ridges touch the line, it is a plain whorl. If none of the center core touches the line, it is a central pocket whorl.

8 Whorls Part 2 Double Loop Whorl Accidental Whorl Delta Delta Double loop whorls are made up of any two loops combined into one print. Accidental whorls contain two or more patterns (not including the plain arch), or does not clearly fall under any of the other categories.

9 Identify each fingerprint pattern. Left Hand Right Hand Right Hand Right Hand Left Hand

10 Lab Write Up Title: Fingerprint Lab Problem: Which is the most common type of fingerprint in our class?

11 3 Types of Fingerprints Loops 60-65% of people Whorls % of people Arches 5 % of people `

12 Hypothesis Hypothesis: If then because If each person finds their fingerprint type, then the (loop whorl, arch) fingerprint will be the most common because

13 Variables Independent Variable (the one thing you change) the type of fingerprint Dependent Variable (the one thing you measure) the number of fingerprints/percentage of fingerprints

14 Materials 1 piece of scratch paper 1 pencil 1 magnifying glass 1 roll of clear tape

15 Procedure 1. Rub the pencil on the scratch paper until there is a smudge of graphite the size of your fingertip. 2. Select which hand you will take fingerprints from. 3. Beginning with your thumb. Rub it on the smudge until your thumb is covered in graphite. 4. Place a small piece of tape over your thumbprint and press down gently. 5. Carefully remove the tape and stick it in the appropriate square on your data table. 6. Repeat the process for the other 4 fingers of your hand. 7. Look at your fingerprints and identify which type of fingerprint you have. 8. Record the group tallies for each type of fingerprint and then find the total and percentage of each.

16 Data Loop TABLE DATA

17 Identify your type of fingerprint `

18 Loop

19 Graph Create a Bar Graph of your group data in Google Spreadsheet. (You will copy this graph into your Lab Doc) Title the Graph: Fingerprints Title the X- Axis: Types of Fingerprints Title the Y-Axis: Percentage of Students Remember Percentage is the Number of the Type divided by the Total Number of Fingerprints. Ex: 4 Loops from the group/10 Total Fingerprints from the Group =.4 Then multiply.4 x 100= 40%

20 After you complete your graph and lab report Reflect on the answer to your bellwork question. Add to or revise your answer based on what we learned in this lab. Then answer the following question: How will practicing classification help you understand human body systems? SHARE your Fingerprint Lab document with me.

21 When you are finshed