Centrifuge containing DNA samples in Eppendorf tubes. A centrifuge spins samples very fast causing suspended solid matter, in this case DNA (deoxyribonucleic acid), to separate from the liquid. These samples are being analysed for forensic evidence. For example, the DNA may have been obtained from hair or bodily fluids left behind at a crime scene. A unique 'DNA fingerprint' can be created from such samples, to be compared with that of crime suspects. If a suspect's DNA matches that found at a crime scene, then a connection is proved almost beyond doubt.