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, <cont...@metricpioneer.com> 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 cont...@metricpioneer.com --------- > Date: Fri, 28 Mar 2014 15:06:51 +0000 > From: cont...@metricpioneer.com > Reply-To: cont...@metricpioneer.com > Subject: [USMA:53657] RE: SI Trivia Survey B > > To: "U.S. Metric Association" <usma@colostate.edu> > > 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 <vliets...@btinternet.com> --------- > Date: Fri, 28 Mar 2014 05:41:08 -0000 > From: Martin Vlietstra <vliets...@btinternet.com> > Reply-To: vliets...@btinternet.com > Subject: [USMA:53656] RE: SI Trivia Survey B > To: "U.S. Metric Association" <usma@colostate.edu> > > 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: owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] 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: owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] 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: cont...@metricpioneer.com [mailto:cont...@metricpioneer.com] > 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 <vliets...@btinternet.com> --------- > Date: Thu, 27 Mar 2014 20:46:54 -0000 > From: Martin Vlietstra <vliets...@btinternet.com> > Reply-To: vliets...@btinternet.com > Subject: [USMA:53650] RE: SI Trivia Survey B > To: "U.S. Metric Association" <usma@colostate.edu> > > > 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: owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] On > Behalf Of cont...@metricpioneer.com > 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 <vliets...@btinternet.com> ----- > > David Pearl MetricPioneer.com 503-428-4917 > > > > > ----- End message from Martin Vlietstra <vliets...@btinternet.com> ----- > > David Pearl www.MetricPioneer.com 503-428-4917 > > > > > ----- End message from cont...@metricpioneer.com ----- > > David Pearl www.MetricPioneer.com 503-428-4917 >
