The effect of surface temperature on fingerprints
The hypothesis that fingerprints obtained from a surface with lower temperature will be clearer has been proven to be true.
Fingerprints are now used for identification of individuals and at crime scene investigations. Some banks even use fingerprint detectors to verify the identity of a person before financial transactions are permitted. Access to certain restricted areas may also be controlled by fingerprint scanning. Sometimes, crossing country borders also requires fingerprint identification.
The science fair project may be repeated by using different types of surfaces like marble, PVC or wood finishing.
Fingerprint - http://en.wikipedia.org/wiki/Fingerprint
Fingerprinting - http://www.cyberbee.com/whodunnit/dusting.html