Fingerprint Classification STEM Experiment for Children

Posted By Annamaria French  
00:00 AM

The children love participating in experiments and fingerprint classification is a great STEM experience for them to explore the similarities and differences of their prints. So I have reposted a blog called Fingerprint Classification Project

from HubPages dated May 22, 2008 by Lela Davidson (fingerprint photo sourced from HubPages). I have updated it for younger children.


The Question - How Can We Classify Fingerprints?

It's always a good idea to make an activity fun, so why not play detective and invite your children to find the criminal's fingerprint. You will be amazed at how the children can come up with useful systems of classification.

Fingerprint Facts:

  • The ridge patterns on our finger pads are unique and there are no two that are exactly alike.
  • Whenever we touch anything with a little pressure, our ridge pattern leaves an impression on these surfaces.
  • Fingerprints can be visible, depending on the substances on our fingers, like sweat, other natural secretions (blood) or oil. 
  • The ridge structure always remains the same and does not change when injured, and new skin always grows back in the same pattern.




Fingerprints are classified by patterns, sizes, and by the position of the patterns on the finger. By using the skills of observation, comparing and contrasting, and classification, the children can devise their own system for organising the fingerprint samples.

Materials Needed:

  • 3x5 index cards
  • pencils
  • pencil sharpener
  • transparent tape (3/4-inch if you can get it)
  • good lighting
  • magnifying glass

There are Several Ways to Take Fingerprints Samples:

  1. Use a stamp ink pad. This is a very messy procedure and can damage clothing and room surroundings.
  2. Practical: rub pencil all over a small area of paper or index card to make an "ink" pad, press fingers onto the penciled area, lift prints from fingers with transparent tape, and stick tape to white index cards.

It's always a good idea to make your activity fun, so why not create a mock crime scene with a single print from one of you and find a match by examining every single print. Just remember the children need to find a way to name and classify the fingerprints. Then they have to find the matching print to the one they find at a crime scene. 

The Procedure:

  • Everyone needs to take prints of their index fingers to compare.
  • Make sure the prints aren't of the tips of fingers but of the pads near the joint crease. That's where the most interesting and distinct patterns are.
  • Make sure to label fingerprints with "L" or "R".
  • Take prints until you get something clear enough to see the pattern.
  • Collect the fingerprint at the crime scene using sticky tape.
  • After all the prints are made and labeled, compare the prints for similarities and differences.


Questions You Could Ask:

  • Are the two prints from the same hand more alike than prints from different people? 
  • What kinds of patterns do you see? Label them.
  • What are the positions of those patterns on the finger?
  • Compare the size of those patterns.
  • Ask which is the most common pattern.


After the children have compared all the finger prints and classified them according to difference and similarities, find the person's fingerprint that matches the one at the crime scene.



Good Luck!