"But still try, for who knows what is possible…" - Michael Faraday
Phase of the Moon today: Waning Crescent 35% of Full
Because of the work on Faraday and Maxell and their connections of electricity to magnetism allowed the understanding of EMR - electromagnetic radiation - with this understanding comes technology to study this phenomenon - one type being the spectrometer.
Using an ALTA spectrometer allows us to identify different rock types by allowing us to measure different wavelengths of EMR (electromagnetic radiation) that reflect off the surface of a rock or other sample. By ‘shining’ light of a specific wavelength on the surface of a rock and measuring the wavelength that has been reflected we can plot light as a function of the wavelength to create a rock spectra curve or graph. This curve allows us to compare samples to known samples or other tested samples and from that we can deduce their composition.
Using an ALTA spectrometer allows us to identify different rock types by allowing us to measure different wavelengths of EMR (electromagnetic radiation) that reflect off the surface of a rock or other sample. By ‘shining’ light of a specific wavelength on the surface of a rock and measuring the wavelength that has been reflected we can plot light as a function of the wavelength to create a rock spectra curve or graph. This curve allows us to compare samples to known samples or other tested samples and from that we can deduce their composition.
The reason this happens is that the rock samples contain materials within that have a defined chemical composition and atomic structure. This material essentially has its own ‘fingerprint’ that can be compared to known samples. When a photon of light hits the surface of the sample the energy of this photon must be conserved according to the principle of conservation of energy. The incoming light is ‘broken up’ into reflected light and absorbed. The ALTA spectrometer allows us to measure this reflected portion of light using a photo detector within the apparatus. The ALTA spectrometer is technically a multiband photometer since it has a limited spectral range (visible to infrared) and senses the reflected light with a silicon photodiode. This diode is connected to a circuit that allows the digitization of the reflectance of light in tenths of a millivolt. This number provides us with a quantitative number to allow us to create a rock spectra described above which allows the identification of rock types.
signing off
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