The article also says that at zero degrees Celsius, the speed of sound in air is 331.6 m/s. (As air warms up , the speed of sound increases). The value 333.3 is between the two and represents 1000/3.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: 29 June 2013 22:48 To: U.S. Metric Association Cc: U.S. Metric Association Subject: [USMA:53007] RE: Flash To Bang (Lightning Distance) Assume? I rarely assume, but I did look it up. According to https://en.wikipedia.org/wiki/Speed_of_sound The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at 20 °C the speed of sound is 343.2 metres per second. Where do you get 333 m/s? David Pearl MetricPioneer.com 503-428-4917 ----- Message from [email protected] --------- Date: Wed, 26 Jun 2013 20:17:21 +0100 From: Martin Vlietstra <[email protected]> Reply-To: [email protected] Subject: [USMA:52992] RE: Flash To Bang (Lightning Distance) To: "U.S. Metric Association" <[email protected]> > Assume that sound travels at 333 m/s. The sound will travel one > kilometre in three seconds. > > > From: [email protected] [mailto:[email protected]] On > Behalf Of John M. Steele > Sent: 26 June 2013 12:45 > To: U.S. Metric Association > Subject: [USMA:52990] Flash To Bang (Lightning Distance) > > > Interesting article on estimating the distance to a thunderstorm: > > http://www.livescience.com/37734-how-far-away-is-lightning-distance.ht > ml > > > She starts with the usual 5 seconds per mile, but she does include a > metric version. I'm not sure I want to multiply by 340 m/s in my head, however. > It might be easier to just divide by 3 for an approximate (and > slightly > conservative) distance in kilometers. > > > She mentions, but perhaps doesn't adequately explain, the variation of > the speed of sound with temperature. That may be why she gives two > values, only one sentence apart. The lower figure is correct at 0 °C, > the higher figure near 20 °C (remember it is cooler aloft, so the > sound is arriving via multiple paths with differing, generally unknown, temperature profiles). > ----- End message from [email protected] -----
