The TV show CSI and its spinoffs have turned forensic scientists into pop heroes. We’ll look at how engineers turned science into a tool forensic scientists use to catch the bad guys – today on Engineering Works!
CSI fans know that forensic scientists can find out a lot from tiny bits of stuff at crime scenes – who that hair belonged to; what kind of paint is on that car bumper; where that bit of dirt came from – the little things that trip up the bad guys.
When Gil Grissom confronts the murderer with the bit of hair that belongs to her, he knows what he’s talking about because of a nifty analytical tool called neutron activation analysis.
Neutron activation analysis uses neutrons from a nuclear reactor to show researchers exactly what stuff is made of. Hair, for instance – the stuff of TV and real-life murder mysteries.
Hair is mostly protein, but it also has tiny amounts of trace elements, as many as 14 of them. The elements in your hair will be different from those in our hair. When neutrons hit these elements, the combination in your hair gives off a pattern of radiation that’ll be different from mine. So Grissom knows it was you and not me that done it.
Neutron activation analysis is used in a lot of other things, from archaeology to semiconductor manufacturing, to identify traces of different substances.
We’ve identified that our time is up for now. See you next time.