All of us know how crooks are caught. We have seen it in film after film: the police inspector matches the fingerprints on the scene of the crime with the suspect’s fingerprints. And the culprit goes to prison.

Fingerprinting has remained one of the best ways to catch a person with a criminal record. The technique was foolproof, for no two people have matching fingerprints — even identical twins.

Unfortunately, things are not so simple any more. Crooks have become smarter and are very careful not to leave fingerprint traces. While some wipe all the surfaces they touch, others prefer using gloves. British police are now using different ways to nab or catch offenders.

Thermal imaging
Thermal imaging

How do they do it? They try to identify inidividuals by the heat patterns of their bodies. There are lots of blood vessels in our body and all of these emit heat in the form of infra-red radiation. The temperature of skin over blood vessels is thus more than that of the surrounding area. One square inch of skin contains up to 15 feet of blood vessels! (If all the blood vessels of an adult were to be laid in a straight line, it would cover more than 160,000 kilometres!)

Using gadgets that detect infra-red radiation patterns, British police can now identify a disguised crook even in a crowded area! Special video cameras programmed to detect infra-red radiation record the heat pattern generated by the person. This infra-red pattern is then fed into a computer which picks up a match instantly from its records. The suspect is identified. With the police hot on their trail, criminals are going to find it rather tough to escape undetected!

282 words | 2 minutes
Readability: Grade 7 (12-13 year old children)
Based on Flesch–Kincaid readability scores

Filed under: science news
Tags: #british, #radiation, #patterns, #fingerprints

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