Procedure:

Go to

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

Toggle the "Graph Values", "Labels" and the "Intensity" options ON

Lower the temperature on the thermometer to its lowest, Earth and start here. Then increase the temperature in the increments below. The objective for all 4 parts of this experiment is to find out:

1) What is the peak radiation wavelength of this object _max, and the intensity, F?

2) In what region of the EM spectrum is this peak? (e.g., UV, Visible, IR) (You may need to zoom in/out)

3) Verify that the peak wavelength and the temperature are in fact obeying Wein's law

4) Verify that the intensity and the temperature are obeying the Stefan-Boltzmann Law

(You need to show that both sides of the equation yield the same number. Show your calculations)

Note that the wavelengths are measured in units of micrometers (m). Remember,

1 m=1000 nm.

1. T=1000K (a little above "Earth")

_max = nm

Does Wein's Law hold?

EM spectrum region:

F=

Does Stefan's Law hold?

1. T=3000K (Lightbulb)

_max = nm

Does Wein's Law hold?

EM spectrum region:

F=

Does Stefan's Law hold?

1. T=5850K (our Sun)

_max = nm

Does Wein's Law hold?

EM spectrum region:

F=

Does Stefan's Law hold?

1. T=9950K (Sirius)

_max = nm

Does Wein's Law hold?

EM spectrum region:

F=

Does Stefan's Law hold?

Compare intensity for the T=1000K object and T=7000K. Can you guess the ratio before plugging in any numbers? Can you confirm F7000/F1000 = (7000/1000)⁴=

(7)⁴ = 2401?