Fingerprints

Fingerprints

Poll

Do identical twins have the same fingerprint?

• Yes

• No

What is a fingerprint?

Fingerprints: The marks left behind when someone touches an object with their fingers. There are three kinds of fingerprints:

• Impression left in something soft, such as putty, soap or wet paint

• Print left by a hand covered in dirt, blood or paint

• Invisible deposit left by the secretions from the skin (oil or sweat)

Labelling

Who owns these fingerprints?

Drag labels to their correct position on the image

Koala

Human

Sweat glands secrete water, amino acids, salt, and urea via tiny pores. Oil also gets secreted.

While the water evaporates, everything else gets left behind. This, plus dead skin cells, are what gets transferred and makes a fingerprint.

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Poll

Does your fingerprint change over time?

• Yes

• No

Multiple Choice

How many types of fingerprint are there?

• One

• Two

• Three

Poll

We can only use the prints from our fingers in forensics.

• True

• False

Every person has their own unique pattern of ridges and furrows. They are found on the outer layers of skin of fingers, thumbs, toes, lips, palms and soles of the feet. There is even a record of a lip print used to identify a car in a 'hit and run' accident in the United States.

The study of fingerprints is called dactylography. The study of lip prints is called cheiloscopy.

Multiple Choice

Ridge patterns are only found on the fingers, hands, toes, and feet.

• True

• False

Open Ended

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Research and Write

You have 10 minutes to research and answer the following question:

When are a person's fingerprints formed and how may they change or be changed over time?

Your fingers looked like this until about 3 months in utero. The shape and size of the 'pads' determine what your fingers look like today!

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Foetal Finger Pads

Because I have a/an ________________ on my thumb, I must have had a/an ________________ volar pad when I was in utero.

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Look at your thumb...

Types of Fingerprint Patterns

60-65% of the population. There is a core with type lines around it and a delta (small triangle where the type lines intersect). All loops must have at least one delta.

Loop

30-35% of the population. Must have a core and at least two deltas.

Whorl

5% of the population. Divided into two types: plain or tetrarch (up-thrusted ridge in the centre of the arch).

Arch

Glue this into your books

Hotspot

Click on the core of this fingerprint.

Hotspot

Click on the delta of this fingerprint.

Match

Match the fingerprint to their key pattern.

Loop

Arch

Whorl

• Loop

• Arch

• Whorl

• Not common

• Mixture of patterns and may have three or more deltas

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Composite Fingerprints

Elimination Prints

Elimination prints are a common practice during an investigation. Obtaining prints from anyone who has a legitimate reasonable reason as to why their prints are found at the scene helps eliminate their prints from the prints found at the scene. Knowing what prints (and who belongs to those prints) streamlines the investigative process by "eliminating" those prints from other prints found not belonging to "authorized" persons.

Why might the fingerprints look wider in an elimination print?

In your own words, describe what an elimination print is and why they are done.

Activity 1: Elimination Prints

Activity 2: Matching Prints