Presented by Group 6: Neal Boseman, Vessen Hopkins, and Sarah Moorman

 What is Blackbody Radiation?  History of Blackbody Radiation  How has this discovery impacted Modern Physics?  Applications of Blackbody Radiation

 German physicist  3/12/1824 – 10/17/1887  Contributed in the Areas of: - Electrical Circuits - Spectroscopy - Blackbody Radiation Image Credit: Hulton Archive/Getty Images

 Spectroscopy - is the scientific study of an object based on the dispersion of said object’s light into its component colors.

1. Hot, dense object will produce a Continuous Spectrum. - This is what Kirchhoff termed a Blackbody. 2. Hot, low density object will produce an Emission Line Spectrum. 3. A cool, low density gas in front of a continuous light source will produce an Absorption Line Spectrum.

 Theorized in 1859 by Gustav Kirchhoff.  An ideal physical body.  Absorbs 100% of all incident radiation and reflects or transmits none.  Emits 100% radiation. Image Credit: NASA

 A Blackbody in thermal equilibrium emits EM radiation termed Blackbody Radiation.  Universal Property: Independent of material used.  Led to relation between radiation intensity ( I ), temperature ( T ), and wavelength ( λ ).  Blackbody Curves  Helped prove thermal radiation was also EM radiation.  Many physicist attempted to characterize shape of Blackbody curve…

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 Wien’s Displacement Law :  Relation between peak wavelength and temperature.  Stefan-Boltzmann Law :  Relation between temperature and the power per unit area.  Rayleigh-Jeans Formula :  Relation between radiation intensity, temperature, and wavelength.  Ultraviolet Catastrophe!

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 Rayleigh-Jeans Formula  Rayleigh-Jeans model failed to comply with experimental data at high frequencies  Wien’s Radiation Law  Wien's model failed to comply with experimental data at low frequencies.

 (Apr to Oct. 1947)  Approach to Blackbody Radiation Problem  Planck’s Radiation Law  Mathematical Trick  h = Planck’s Constant  Discrete Values of Energy: E = nhf Image credit: Hulton Archive/Getty Images

 Led to established relationships between light intensity, wavelength, and temperature:  Wien’s Displacement Law  Stefan-Boltzmann Law  Rayleigh-Jeans Formula  UV Catastrophe  Planck’s Radiation Law  Discrete Values Led to Best Fit for Experimental Data – Planck’s Mathematical Guess  Thus We Have Quantization of Energy: E = nhf  Implications for What’s Occurring at Atomic Level.  Birth of Quantum Mechanics!

 Gave people the ability to calculate temperatures of distance cosmic bodies  Inspired new devices such as thermal vision and new types of thermometers

 Thornton, Stephen T., and Andrew F. Rex. "The Experimental Basis of Quantum Physics." Modern Physics for Scientists and Engineers. 4th ed. Boston, MA: Cengage Learning, N. pag. Print.  Kirchhoff, G. (1860). "Ueber das Verhältniss zwischen dem Emissionsvermögen und dem Absorptionsvermögen der Körper für Wärme and Licht". Annalen der Physik und Chemie 109 (2): 275–301.Bibcode:1860AnP K. doi: /andp Translated by Guthrie, F. as Kirchhoff, G. (1860). "On the relation between the radiating and absorbing powers of different bodies for light and heat". Philosophical Magazine. Series 4 20 : 1–21.  Planck, Max (1901). "On the Law of Distribution of Energy in the Normal Spectrum". Annalen der Physik 4 : 553. Bibcode:1901AnP P.doi: /andp  Fowler, Michael. "Planck’s Route to the Black Body Radiation Formula and Quantization." Lecture. 25 July Web. 1 Dec