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Blackbody Radiation Spreadsheet: available as a plaything....


I've added a 'file share' tab to the menu above, and Rory Geoghegan (a man that can only be described as a Colossus of Irish Science Education) is going to be uploading a number of his files there over the next little while.


There are already several of them up, but a particular favourite of mine is the Blackbody Radiation Spreadsheet pictured here.


It's fully editable, but - being kind to those of us who would struggle (and fail) to set such a thing up - it is fully loaded as it is, and ready for us to play with. The graph in this image shows the radiation emitted by a body at 10K - showing that such a cold body would have a very low power output, and that what little radiation it emitted would be of very long wavelength.


But the slider under the image allows you to vary the temperature and the graph shows the power output against wavelength for a body at the selected temperature. (Alternately you can input a temperature into the yellow box towards the top left). This graph shows the output for a body at 373 K - still only in the Infra Red Range.


One interesting idea is to set it around 300K - which is the approximate temperature for human extremities. A fascinating table under the graph compares the output of the human body and compares it to the energy we can absorb from our surroundings at various temperatures. Apparently the human body operates at about 90 W. Another table beside that compares the energy output of a human hand (about 4.6 W) to that of a mobile phone mast (about 0.2 W).


There's so much to learn from this one page excel doc. I've been playing around with it for an hour or more and there's still a lot I haven't explored. But, crucially, though I can continue to learn from it for ages, its already in a state where I can begin teaching from it.


This last graph shows the output at 6000 K - which a not-always-reliable online encyclopaedia tells me is the temperature at which Dicyanoacetylene burns in Ozone. that graphs shows us what colours would be present in its visible flame.










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