Fingerprint Lake

T. Trimpe 2006 http://sciencespot.net

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.

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

Interesting Info

Did you know?

Dactyloscopy is the study of fingerprint identification.

Police investigators are experts in collecting

“dactylograms”, otherwise known as fingerprints.

Fingerprint Factoid:

60% of people have loops, 35% have whorls,

and 5% have arches

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.

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.

Spike or “tent”

Loops

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.

Delta

L – Radial Loop
R - Ulnar Loop

L – Ulnar Loop
R - Radial Loop

Radius

Ulna

Left
Hand

X-Ray Imagine: http://www.tooloop.com/wp-content/uploads/2013/12/Radius-Ulna-X-Ray.jpg

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.

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.

Plain
Whorl

Central
Pocket
Whorl

Whorls – Part 2

Accidental Whorl

Accidental whorls contain two
or

more

patterns

(not

including the plain arch), or
does not clearly fall under any
of the other categories.

Double Loop Whorl

Double loop whorls are
made up of any two loops
combined into one print.

Delta

Delta

Identify each fingerprint pattern.

?

A

B

C

D
E

Right Hand

Left Hand

Left Hand

Right Hand

Right Hand

It’s time to make

some prints!

Avoid
Partial
Prints
GOOD PRINT

Get as much of the top part
of your finger as possible!

Directions

1st – Roll the “pad” portion of your thumb over the
ink pad from the left side of your thumb to the
right. You do not have to push down really hard!

2nd – Roll the “pad” portion of your thumb from the left side of
your thumb to the right in the correct box on your paper to make a
thumbprint.

3rd – Continue this process to make a fingerprint of all ten fingers
on the “My Prints” worksheet.

4th –Use your notes and a magnifying lens to help you figure out
what type of pattern is found in each of your fingerprints. Label
each one with the pattern’s name.