Uses of the Spectrometer

A spectrometer measure properties of light (i.e. its wavelength) over a specific portion of the electromagnetic spectrum. According to Beer's law, the amount of light that can pass through a medium is proportionate to the concentration of the light-absorbing material or solute. Using the spectrometer, we can measure the intensity of light that passes through a certain material and figure out its properties. This is process is called 
spectrophotometry. 



There are many uses for the spectrometer in chemistry, physics, biology and material science and astronomy. These are some common and interesting applications of the spectrometer in different fields of study: 


In chemistry:

Atomic spectrometry: A technique used to study atoms and molecules. Each atom will absorb or release different amounts of energy depending on the number of electrons it has and thus emit or absorb photons in a unique pattern. By studying the light's wavelength and intensity, we can deduce the type of atom that is in a sample.  


Ultraviolet Visible spectrometry: Electrons of different energy levels can absorb energy in the form of ultraviolet or visible light. Using a spectrometer, we can study the properties of light that passes through a solution and determine the concentration of absorbing species in a solution. 


Infrared spectrometry:This technique deals with infrared light, which has longer wavelength and lower frequency than visible light. It is also used to study and identify chemicals and is used in both organic and non-organic chemistry. 


In forensics:


With new innovation and technology comes new methods of investigating crime. Spectrometry has many uses in forensics. One example is to detect how much alcohol is present in a suspected drunk driver's blood, by identifying and analysing polymer degradation. Infrared spectrometry can also be used to study solid samples and solutions. The sample is pressed against a single crystal and infrared radiation passes through the crystal and interacts with the sample. The properties of the sample can be determined by studying the interaction between the light and the sample. Technology like this and countless others help in forensics investigation and provide evidence to solve crimes.  



In astronomy: 

The spectrometer is the one of the most powerful and widely used tool in astronomy,and is usually used in conjunction with a telescope. Almost all of our knowledge of the universe chemical makeup came from the spectrometer. Stars and other celestial objects emit or reflect light, a form of electromagnetic radiation. By studying the light coming from these celestial objects, we can determine or estimate many of its properties, such as distance, temperature, composition, and speed at which it is moving. When light passes through an atmosphere of gas, light is absorbed. Depending on the gasses present in an atmosphere, the wavelengths of light absorbed or emitted will be different. Dark bands in the spectrum means that energy is absorbed by an object, while bright lines usually mean the object is emitting light. Using a spectrometer, we can deduce the composition of celestial bodies, such as stars and planets. This technique is used to search for 'Earth-like' planets which may potentially sustain life. By studying the light reflected off the planet using powerful telescopes, scientists can determine the composition of the planet's atmosphere. This method proves to be useful as it allows us to study planets from light-years away without physically sending machines or humans there. As more powerful telescopes are developed, we can look further into the universe and study distant planets and stars more extensively. 

(European Extremely Large Telescope (E-ELT) located in Cerro Armazones, Chile)