JM: Every day, we leave an imprint on whatever we touchdoorknobs, keyboards, glasswareitâ€™s our own unique set of fingerprints. Iâ€™m Jim Metzner, and this is the Pulse of the Planet. Now, if the prints we leave happen to be within the vicinity of a crime, then itâ€™s time to call in a fingerprint examiner like David Tate. David works at the Onondaga County Center for Forensic Science in Syracuse, NY. To help make those prints visible, and to preserve them as evidence, heâ€™ll use a familiar substance in an unfamiliar way.
DT: So, Iâ€™m going to put this superglue right up there, and thatâ€™s a hotplate. Itâ€™s just going to heat up the superglue, turn it into vapors. Close the door and make sure itâ€™s shut. And we wait about 15 minutes or so, and then we should have a fingerprint.
JM: David has placed a glass slide with an invisible fingerprint on it into this Super Glue chamber. The chemical vapors adhere to the print and harden it to the glass.
DT: All right. So, itâ€™s time to check our Super Glue slide.
[taking superglue slide out of machine]
DT: As you can see, itâ€™s a lot whiter than it was before. And Iâ€™m going to apply a dye stain to it. And this dye stainâ€™s going to help us be able to see this fingerprint a lot easier than what we saw before. So I spray it on, make sure itâ€™s covered. This is an alcohol-based liquid, so the alcoholâ€™s going to evaporate really quickly. Just going to hang this back here to dry, and after a few minutes that should be good to go.
JM: After a few minutes, a second dye is applied.
DT: Looks yellow, and weâ€™re going to throw a ultraviolet light on it. Itâ€™s going to help us be able to see it very easily.
JM: Once a fingerprint is isolated and made visible, it can be photographed, and then compared to known prints, to hone in on a suspect.
David Tate is a participant in this yearâ€™s Kidsâ€™ Science Challenge, our free nationwide competition for 3rd to 6th graders, made possible by the National Science Foundation. Log on to kidsciencechallenge.com, where you can download some safe, non-toxic fingerprint activities that you can do at home. Iâ€™m Jim Metzner.