Fingerprint Detective: Loops, Whorls, and Arches
Press your thumb against a window, then look closely. You just left a tiny map made of curved lines called ridges. Here is the amazing part: out of the more than 8 billion people on Earth, not one has fingerprints exactly like yours. Even identical twins, who share the same DNA, have different fingerprints! That is why detectives get so excited when they find prints at a crime scene. Those little curves can point to exactly one person.
What You'll Learn
In this lesson you will: - Name the three main fingerprint patterns. - Explain why fingerprints are used to identify people. - Lift and compare fingerprints like a real forensic scientist.
Three Patterns to Know
Almost every fingerprint fits into one of three groups. Loops curve in from one side, make a turn, and go back out the same side. About 6 out of every 10 people have loops, so they are the most common. Whorls look like a target or a whirlpool, with circles around a center point. About 3 out of 10 people have whorls. Arches rise up in the middle like a small hill or wave, with no loop or circle. These are the rarest, found in only about 1 out of 20 people.
To see your own pattern, rub a pencil on paper to make a gray patch, press your fingertip on it, then press that finger onto clear tape. Stick the tape on white paper and look for a loop, whorl, or arch!
Why Fingerprints Never Change
Your fingerprints formed before you were even born, while you were growing about four months in. Once they formed, they stayed the same. Your fingers grow bigger as you grow, but the pattern of ridges does not change. A scientist named Sir Francis Galton showed in 1892 that everyone's prints are different. Today, computers can compare a print to millions of others in just seconds.
Match each fingerprint pattern to its clue.
Terms
Definitions
Drag terms onto their definitions, or click a term then click a definition to match.
Which fingerprint pattern is the most common?
Why can fingerprints help identify exactly one person?
Make a Fingerprint File
With a grown-up's help, use a pencil and clear tape to lift a print from each of your ten fingers onto a sheet of paper. Label each one. Then look at every print with a magnifying glass and write L for loop, W for whorl, or A for arch next to it. Count how many of each pattern you have and share which one is most common on your own hands.
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