PAR is explained here: http://www.vernier.com/products/sensors/solar-radiation-sensors/par-bta/ I also see it related to aquarium lighting like here: http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=30196&cmpid=03csesz&ref=3474&subref=AA&CA_6C15C=530005150000177888 I am not defending the author of the site below as a few symbols are not right.
John Altounji One size does not fit all. Social promotion ruined Education. http://bit.do/tounj From: Aubrecht, Gordon [mailto:aubrech...@osu.edu] Sent: Wednesday, August 3, 2016 3:20 PM To: John Altounji <phy...@msn.com> Cc: Stanislav Jakuba <jakub...@gmail.com>; U.S. Metric Association <usma@colostate.edu> Subject: Re: [USMA 287] Puzzled Hi, folks, What is PAR? They forgot time in their last equation. They did a rotten unit job in addition. umoles? micromoles of photons? of what? (I’m a bit perplexed here) sec? Watts? KJ? Who are these people? They do not know a lot about units, it seems. (This sort of reminds me of that Sam Cooke song Wonderful World—“Don’t know much about history, don’t know much biology, don’t know much about a science book, …”) Gordon On Aug 3, 2016, at 3:14 PM, John Altounji <phy...@msn.com<mailto:phy...@msn.com>> wrote: I found this: http://www.pnet.sr.unh.edu/subpages/radconvert.html They probably forgot the square. John Altounji One size does not fit all. Social promotion ruined Education. http://bit.do/tounj From: USMA [mailto:usma-boun...@colostate.edu] On Behalf Of Stanislav Jakuba Sent: Wednesday, August 3, 2016 11:57 AM To: U.S. Metric Association <usma@colostate.edu<mailto:usma@colostate.edu>> Subject: [USMA 286] Puzzled Below is a quote from a scientific paper about measurements of energy in an average lighting strike. My question: What's MJ/m? Stan "The energy released by lightning is measured in megajoules, also expressed as MJ/m." “For example a single megajoule is equivalent to about 200 food calories, or the energy from leaving a microwave on for 20 minutes to cook food,” he explains. “It can also be compared to a 60 watt lightbulb’s energy use if left on for about four hours. It’s also the same as the kinetic energy a car has traveling about 60 mph.” Their research found that the energy produced by a lightning strike peaked at greater than 20MJ/m. _______________________________________________ USMA mailing list USMA@colostate.edu<mailto:USMA@colostate.edu> https://lists.colostate.edu/cgi-bin/mailman/listinfo/usma ######################### Gordon Aubrecht Professor of Physics, OSU OSU Physics (614) 292-2574, FAX (614) 292-7557 Marion Campus (740) 725-6250, FAX (614) 292-5817 aubre...@mps.ohio-state.edu<mailto:aubre...@mps.ohio-state.edu> check out my web sites through my home page http://www.physics.ohio-state.edu/~aubrecht Read my book Energy (Prentice-Hall, 2006) and visit the PH Energy website http://www.pearsonhighered.com/educator/product/Companion-Website-for-Energy-Physical-Environmental-and-Social-Impact-3E/9780131403727.page However beautiful the strategy, you should occasionally look at the results.--Sir Winston Churchill As a rule we disbelieve all the facts and theories for which we have no use.--William James (1842 - 1910) Science is not just a career or a body of facts, but, more important, a set of cognitive and practical tools designed to understand brute reality while overcoming the human desire to believe what we like or find emotionally satisfying. —Jerry A. Coyne, in Faith vs. Fact: Why Science and Religion Are Incompatible (2015)
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