Video briefly explaining Raman spectroscopy in forensics. (Multimedia 3) 

Wavelengths or frequencies of radiation are absorbed by matter at different levels, and scientists can use machinery to measure those levels. Everything reacts differently to light. By using these properties, investigators can better identify and understand strange substances that they come in contact with in their investigation. There are numerous machines that can be used, and only a few are listed here.

Raman Spectroscopy

"Some vibrations are infrared inactive. These vibrations may, however, be active in Raman spectroscopy, which is a companion technique to infrared spectrophotometry. The Raman effect involves radiation in the UV/visible range. Instead of absorbing this radiation, the molecule causes it to be scattered." (Citation 14)

Mass Spectroscopy

When energy in a certain form is transferred to matter, positive ions are created. Depending on the amount of energy, the ions may either remain stable or fragment until they are stable. The result of this is called the mass spectrum and creating it is called mass spectrometry. "Mass spectrometry has two very important properties that make it a valuable tool in analytical chemistry and thus in forensic chemistry.

1. If the energy of the source is carefully controlled and constant, then the fragmentation pattern for a given substance will be very reproducible.

2. The fragmentation pattern for most substances is unique. The mass spectrum of a pure substance is a reliable way of identifying it." (Citation 14)

Video on spectrometry. (Multimedia 4)