Computer, Ocean Optics Spectrometer, CFL light bulbs - 2700K, 5000K, 6500K, and Variacs.
2700k Bulb Spectrum

2700k Bulb

5000k Bulb Spectrum

5000k Bulb
6500k Bulb Spectrum

6500k Bulb

 

Code Number: 6B40.30

Demo Title: Black Body Radiation

Condition: Excellent

Principle: Blackbodies

Area of Study: Optics & Astronomy

Equipment:

Computer, Ocean Optics Spectrometer, CFL light bulbs - 2700K, 5000K, 6500K, and Variacs.

Procedure:

See also: 6B40.30 in Astronomy.

Turn the lights on, let them warm up for a few seconds, and point the spectrometer sensor cable at the desired light.  Set the spectrometer to a boxcar setting of about 100.  A broad Black Body radiation curve can then be seen.  The peak of that curve will shift to different wavelengths as you look at the different Kelvin rated bulbs.

References:

  • I. Gonzalez de Arrieta, "Wien's Displacement Law and Blackbody Radiation Quartiles", TPT, Vol. 59, #6, Sept. 2021, p. 464.
  • "Figuring Physics", TPT, Vol. 40, # 4, Apr. 2002, p. 252.
  • MIT Physics Department, "Blackbody Radiation - The Stefan-Boltzman Law", Junior Physics Laboratory Experiment #002, June 4, 2001.

Video and Editing Credit: Jonathan M. Sullivan-Wood.

6B40.30 - Black Body Radiation