This project is an entertaining way for students to examine the three different categories of fingerprint patterns and how fingerprints are indicative of identity. Start by scripting a short murder mystery in which an individual is the victim of a pencil-stabbing; fingerprints are found at the scene of the crime on the pencil sharpener. Pass out copies of the fingerprints found and appoint half of the students as investigators and half of the students as suspects. The investigators take the prints of the suspect, and as a team the pair compares and contrasts the different aspects of the fingerprint patterns: loop from left, loop from right, arches, whorls and double loop. The suspect whose fingerprint pattern most closely matches the fingerprint pattern found on the pencil sharpener is the culprit.
This experiment compares the fingerprints of siblings and the fingerprints of unrelated individuals to determine if fingerprints are inherited or random. Students take fingerprints from the index fingers of fifteen pairs of siblings and fifteen pairs of people who don't share the same biological parents. Using the three general categories of fingerprint patterns -- loop, arch and whorl -- they record observations about the prints taken from each individual, noting the similarities and differences found among the individuals in each pair. At the conclusion of the experiment, there should be more similarities among the siblings, thus indicating that fingerprint pattern is influenced by genetics.
The fingerprint pattern commonality project aims to teach students about probability while investigating which fingerprint pattern is most common. Students take prints from a large sample size and categorize results according to one of three dominant patterns: loops, arches and whorls. They then use the data collected to calculate the probability of each fingerprint pattern. As a secondary objective, students learn about the effect of unexpected variables on an experiment. In this particular experiment, fingerprints could become smudged and patterns unidentifiable, a variable that could complicate results.
Fingerprint visualization, the process of making latent fingerprints visible to the human eye, is one of the most important responsibilities of a forensic scientist. In this project, students simulate the role of these professionals by using iodine fuming to reveal otherwise invisible fingerprints. A carefully weighed piece of iodine crystal is placed in a long glass tube and heated by a Bunsen burner until the point of sublimation. When a sample of white paper with invisible fingerprints is inserted into the tube, the secretions left from the ridges of the prints absorb the iodine and appear in a yellowish color. Students should wear protective gloves and goggles as iodine fumes are toxic and corrosive.