How does forensic science help us?

Well the big one is at a crime scene, they can take a sample of DNA and run PCR on the sample. Then it can be matched with the DNA of a suspect.

OR

If you want to be on Maury Povich and prove he's your baby daddy.. hahaha

Eventually, Forensic Science can help us to find out the truth in matter of the law. How? Forensic Scientists do various tests on the evidence, use different equipments and techniques to examine/identify/compare the evidence. The result can help to reconstruct the scene, prove or disprove someone's testimony, and of course, sometimes the result is inconclusive.

DNA tests of all kinds. watch some CSI to see how it helps

Forensics is most important in my opinion to police work, with the right information a FS can determine time of death, weapon, the exact specifics of the body's toxicology including what they ate, when they ate it, and where it was made even. Along with being experts at DNA analysis and fingerprinting, FS's are a force to be reckoned with against crime.