View https://phet.colorado.edu/sims/html/blackbody-spectrum/latest/blackbody-spectrum_en.html

Set Up Directions

1) Navigate to the link above.

2) Enable "Graph Values", "Labels", and "Intensity" by checking the three boxes near the center of the screen and to the left of the Blackbody Temperature control.

Measurement Directions

1) Learn how to control the wavelength axis of the graphical display by clicking on the magnifying glass below the right hand side of the horizontal axis.

2) Learn how to control the Spectral Power Density axis of the graphical display by clicking on the magnifying glass to the left of the top of the vertical axis.

3) Use the Blackbody Temperature control on the right hand side to move the temperature to each of the temperatures listed in Tables 1 and 2.

4) Enter the peak wavelength of the emitted radiation at each temperature into the appropriate cells of row 2 in Table 1. The peak wavelength is shown in yellow at the bottom of the graph.

5) Enter the Intensity of the emitted radiation at each temperature into the appropriate cells of row 2 in Table 2. The Intensity is shown in white right below the check marked option "Intensity" to the left of the Blackbody Temperature control.

Table 1 Blackbody Temperature and Peak Wavelength

Temperature (K)	300K	3,000K	6,000K
Peak Wavelength, ()
Ratio of Temperatures	300/300=1	3000/300=	T6000300=
Ratio of peak wavelengths	300/300=1	3000/300=	6000/300=

Table 2 Blackbody Temperature and Intensity of Emissions.

Temperature	300K	3,000K	6,000K
Intensity ^2	300=	3000=	6000=
Ratio of Temperatures	300/300=1	3000/300=	6000/300=
Ratio of Intensity	300/300=1	3000/300=	6000/300=

Analysis Instructions

1) Divide the temperatures of 3000K and 6000K by 300K and enter your calculated values in ro2 3 of both Table 1 and Table 2 as indicated.

2) Divide the peak wavelengths of 3000K and 6000K by the peak wavelength of 300K and enter your calculated values in row 3 of Table 1 as indicated.

3) Divide the peak Intensity of 3000K and 6000K by the Intensity of 300K and enter your calculated values in row 3 of Table 2 as indicated.

Conclusion

1) What happens to the peak wavelength of a blackbody as the temperature is increased?

2) Which of the following relationships best fits your data? Is the wavelength, proportional to: a) T2 b) T c) T-1 d) T-2

3) Consider any difference between the measured and theoretical value of the value m=1 in row 3.

4) What happens to the intensity of the radiation from a blackbody as the temperature is increased?

5) Which of the following relationships best fits your data? Is the Intensity proportional to: a) T4 b) T c) T-1 d) T-4