Or rather, answers b and c are both correct.
From: [email protected] [mailto:[email protected]] On Behalf Of Eric L Shuman Sent: 28 March 2014 15:42 To: U.S. Metric Association Subject: [USMA:53659] RE: SI Trivia Survey B Question #1 is just fine as is. If you *really* insist on splitting hairs, then "They are almost precisely the same weight." In the context of promoting the SI, quibbling over 28 mg is a ludicrous own goal when the weight of a gallon of water is a non-trivial, real world problem that people would be happy to accept a 0.028 % margin of error on. Camping, biking, hiking, travelling with pets, weighing milk or water in the kitchen. Working with liquids in all of these contexts can be made much, much simpler by using SI, and it is that which we need to promote. ES On 28 March 2014 08:26, <[email protected]> wrote: One liter of water has a mass of almost exactly one kilogram when measured at its maximal density, which occurs at about 4 °C. Similarly: 1 milliliter of water has a mass of about 1 g; 1,000 liters of water has a mass of about 1,000 kg (1 ton). This relationship holds because the gram was originally defined as the mass of 1 mL of water. ----- Message from [email protected] --------- Date: Fri, 28 Mar 2014 15:06:51 +0000 From: [email protected] Reply-To: [email protected] Subject: [USMA:53657] RE: SI Trivia Survey B To: "U.S. Metric Association" <[email protected]> The question is intended to familiarize Americans with the basics. In normal, daily routine, like cooking, shopping, et cetera, Americans need to know the basics, not rocket science. ----- Message from Martin Vlietstra <[email protected]> --------- Date: Fri, 28 Mar 2014 05:41:08 -0000 From: Martin Vlietstra <[email protected]> Reply-To: [email protected] Subject: [USMA:53656] RE: SI Trivia Survey B To: "U.S. Metric Association" <[email protected]> I think that David was trying to create a variation of the question - "Which is heavier, a pound of feathers or a pound of gold" - the answer is "a pound of feathers" because gold uses troy weight and there are 12 troy ounces in a troy pound. I was drawing on my experience as a computer programmer where it was drummed into me - NEVER test two real numbers for equality only unless you really mean "exactly equal". As one wag put it - "0.1 x 10.0 gives a number which is approximately 1". -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of John Altounji Sent: 27 March 2014 22:26 To: U.S. Metric Association Subject: [USMA:53655] RE: SI Trivia Survey B I don't understand all this discussion. The same is fine if you go 3 significant digits. Density of liquid water Temp (°C) Density (kg/m3)[20][21] +100 958.4 +80 971.8 +60 983.2 +40 992.2 +30 995.6502 +25 997.0479 +22 997.7735 +20 998.2071 +15 999.1026 +10 999.7026 +4 999.9720 0 999.8395 −10 998.117 −20 993.547 −30 983.854 The values below 0 °C refer to supercooled water. Source Wikipedia. I would say you may add room temperature, though not necessary. John Altounji One size does not fit all. Social promotion ruined Education. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Martin Vlietstra Sent: Thursday, March 27, 2014 3:10 PM To: U.S. Metric Association Subject: [USMA:53654] RE: SI Trivia Survey B Hi David, There are two options - one is not to have asked the question, the other is to have used the word ("about the same (dependant on temperature)" rather than "the same" ). Regards Martin -----Original Message----- From: [email protected] [mailto:[email protected]] Sent: 27 March 2014 21:07 To: Martin Vlietstra; U.S. Metric Association Subject: Re: [USMA:53650] RE: SI Trivia Survey B Martin. I am trying to educate Americans, not split hairs. Would it be better to rephrase the question with all that hair-splitting detail? Surely they would fall asleep! How would you more accurately ask the question? ----- Message from Martin Vlietstra <[email protected]> --------- Date: Thu, 27 Mar 2014 20:46:54 -0000 From: Martin Vlietstra <[email protected]> Reply-To: [email protected] Subject: [USMA:53650] RE: SI Trivia Survey B To: "U.S. Metric Association" <[email protected]> Hi David, I wish to dispute the answer to the first question. According to Wikipedia (https://en.wikipedia.org/wiki/Density_of_water#Density_of_water_and_i ce), water at 4 °C has a mass of 0.99970 kg. As it either gets hotter or colder, it expands, making a litre of water less than 0.99970 kg. Moreover, if the weighing is done in air, then then the gold displaces less air than water (it is more dense), so, by Archimedes principle, the water receives a greater upthrust due to buoyancy in air than does the gold. Therefore, a kilogram of gold weighs [very slightly] more than a litre of water. Regards Martin -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: 27 March 2014 17:22 To: U.S. Metric Association Subject: [USMA:53649] SI Trivia Survey B Second one in a series: SI Trivia Survey B: https://t.co/Vvex57DK6L David Pearl www.MetricPioneer.com 503-428-4917 David Pearl MetricPioneer.com 503-428-4917 ----- End message from Martin Vlietstra <[email protected]> ----- David Pearl MetricPioneer.com 503-428-4917 ----- End message from Martin Vlietstra <[email protected]> ----- David Pearl www.MetricPioneer.com 503-428-4917 ----- End message from [email protected] ----- David Pearl www.MetricPioneer.com 503-428-4917
