|MadSci Network: Physics|
Dear Alex, I’m an astronomer/chemical physicist by training and solid state physicist by vocation. Until receiving your question, I really hadn’t thought much about ambient light effects on birds. Then, I started reading about nocturnal lighting on the avian environments. Fine sources of direct research can be found at these websites… => http://www.flap.org/new/nocturnfr.htm => http://www.darksky.org/links/enviro.html#birds As these websites point out structural hazards are actually responsible for more bird kills than higher profile catastrophes such as oil spills. In the dark, and especially in foggy or rainy weather, the combination of glass and light becomes deadly. Confused by artificial lights, blinded by weather, and unable to see glass, birds by the hundreds and even thousands can be injured or killed in one night at one building. “Over 140 different species of birds have collided with buildings in Toronto alone.” It’s estimated that… “across North America, up to 100 million birds die in nocturnal collisions each year.” Wow! So, I think finding out more about the typical ambient lighting conditions for singing birds is an extremely worthwhile endeavor. There are a couple of way to do this. Your idea about using filters, such as camera filters, and a lightmeter could be a first approach in judging the relative intensities of “reds” versus “blues” or “greens”. A more precise approach would be to use a simple inexpensive spectrometer such as sold by Edmund Scientific in the USA. I quote their description and website here… => http://www.scientificsonline.com/product.asp_Q_pn_E_3082305 “Precision Economy Spectrometer Accurate spectral measurement at a brilliant price! Durable, hand-held plastic spectrometer that can be used to identify elements in flame spectra, solar spectra, and various lights (take a look at neon through them!). Easily calibrated to an accuracy within 1 nanometer. Includes reference label for bright spectral lines.” It seems this would be fine for analyzing street lights spectra. However, I don’t think that nocturnal light settings may not produce the intensity necessary for this device to produce useful spectra for the naked eye. You might tinker with using a small CCD camera or “WebCam” in conjunction with this spectrometer for additional sensitivity and record spectra to a PC. This may take some work with an imaging optic to focus the spectrum on the CCD. Beyond this one could move towards acquiring a CCD spectrometer. OceanOptics in Florida makes a fine series of such spectrometers. They even award grants to high school and other institutions for light-based experimentation. In the UK, they are particularly involved in deep sea imaging and spectrometry. See their website… => http://www.oceanoptics.com/ And also this website on the recorded spectra of typical street lights… => http://jchemed.chem.wisc.edu/Journal/Issues/1997/Sep/abs1070.html Finally, it wouldn’t hurt for you to become more familiar with spectroscopy and spectra, in general. There’s a “Beginner’s Corner” for that at these websites… => http://www.colorado.edu/physics/2000/quantumzone/ => http://webexhibits.org/causesofcolor/1H.html => http://www.800mainstreet.com/spect/emission-flame-exp.html Good Luck Alex! ---* Dr. Ken Beck
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