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The Science oF Fingerprints

Young people love doing forensics, and it’s fun to learn how to explore the science of fingerprints.

Why do we have fingerprints?

All primates, including apes, monkeys and humans have fingerprints. Some monkeys even have “fingerprints” on their tails.

Fingerprints are made of lots of small ridges that provide traction to help us grab things.

You can demonstrate this by picking up a piece of paper with one finger. (In dry climates, it works better if you lick your finger first.) Try to pick up a piece of paper with the back of your finger-- it’s impossible!

Making Fingerprints

It’s easy to make fingerprints.

  • Rub a pencil on a piece of paper.
  • Rub your finger over the graphite.
  • Use a piece of tape to remove the graphite from your finger.
  • Tape the fingerprint onto a piece of paper.

Categorizing fingerprints

Classify the fingerprints using the chart below. If you find a fingerprint that doesn’t fit one of these categories call it Eclectic (E).

The science of fingerprints

Solving the crime

Now you're ready for one of my favorite 7th grade science projects -- solving the crime.

Write a short mystery in which you are stabbed to death with a sharp pencil, and some fingerprints are found on the pencil sharpener.

Provide the students with the prints from the pencil sharpener, so the kids can get fingerprints from the suspects and analyze them to identify the murderer. (Assign one student for each suspect. Fingerprints xerox very well, so it’s easy to provide copies for everyone.)

Going further

Forensic scientists look more closely at the fingerprint ridges, looking for features like “forks,” “eyes,” ‘dots,” “bridges,” and “ending ridges.”

Some students will enjoy making a positive match. In most states, you need 12 of these “small features” to make a legal match. This is a good extra credit 7th grade science project, as some students will find it tedious.

7th Grade Science Fair Projects on Fingerprints

Here are some more 7th grade science projects involving the science of fingerprints.

  • Does race influence fingerprints?
  • Do members of the same family have similar fingerprints?
  • Do identical twins have similar fingerprints?
  • Is a person’s fingerprint pattern related to their toeprint pattern?

If students show interest in fingerprint examination, then they may enjoy a future in the law enforcement field. Some careers they may want to pursue are crime scene investigation, criminology, forensic science, private investigation, or even working as a DEA agent, FBI agent, police officer, or US marshal. Getting their masters in criminal justice and/or their masters in political science is a goal that will help them enter this field and become a fingerprint classifier.

Still want to learn more about the Science of Fingerprints?
Then download our Free E-book.
It is almost 400-pages long and loaded with information.

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