ABSTRACT
USEFUL PRIOR WORK: The children do not need to have any particular prior knowledge before completing this investigation.
BACKGROUND SCIENCE: All humans (and some primates) are born with fingerprints that remain the same throughout their lives. The fingerprints are actually caused by ridges of skin and are thought to play a part in transmitting nervous impulses from the skin on our fingers. Fingerprints are unique to an individual, meaning that no two people have the same fingerprints – not even identical twins. This allows people to be identified from fingerprints that they leave behind at a crime scene. Fingerprints can be left on lots of different surfaces, but are most commonly found on smooth, shiny surfaces such as glass. The fingerprint that is left behind is caused by perspiration and grease from the fingers. It can be lifted off a surface by using a powder and special tape. In forensics, aluminium powder is used. This, however, is expensive so iron powder or flour can be used instead. Normal Sellotape can be used to lift the print. The tape can then be stuck onto a piece of card so the print can be viewed.
