1. Spectroscopy

2. Electromagnetic Radiation
Light travels in waves
Highest point in wave = crest
Distance b/t 2 crests = wavelength
Frequency = how many waves pass a specific point w/in a given time
ex. High freq = short wavelength

3. Types: visible light, X rays, radiowaves, microwaves
Used for:
- latent fingerprints
- trace evidence on clothes
- structure of a molecule

4. Spectroscopy Used to: - ID fibers & trace evidence
- detect contaminants, accelerants, explosive residue
Measures wavelength of light emitted & captures image (lines) on photographic film

5. Each element produces a unique pattern of lines – tells which elements are found

6. TYPES:
1. Mass spectroscopy – IDs atoms and molecules by their mass
- forms ions which are sent through a magnetic or electric field
- the path depends upon ratio of mass to its charge --- recorded on photographic plate

7. 2. Atomic absorption spectroscopy (AAS) - determines heavy metal contaminants in air, water, soil samples; also, analyzing paint chips - measures amount of light of a specific wavelength absorbed by atoms of a particular substance

8. 3. Ultraviolet (UV) spectroscopy
- determines concentration of different elements in a solution
Measures wavelengths of light; graph made compared to known for quantitative analysis
Detects drugs in blood or urine; analyzes components of dyes & food additives; monitors air and water quality