The scale is showing not only the mass of the blood inside the bag, but of the bag itself, which mass is constant. These were spring scales with a dial and did not have the zero-out feature of a home kitchen scale. And I forget exactly at what reading the blood taking was considered “done” (I was on my back with a needle in my arm), so it may not have been exactly 600 g. The main thing is that they were using mass to determine how much blood to take and that it was shown in grams.
cm From: Jeremiah MacGregor [mailto:[email protected]] Sent: Saturday, March 14, 2009 11:43 To: [email protected]; U.S. Metric Association Subject: Re: [USMA:43812] Re: 24 hour time The density of blood seems to have some variance but if we assume it is close enough to 1100 kg/m^3 (=1.1 kg/L), then we can calculate that 450 mL of blood would have a mass of 495 g and a 600 g mass would have a volume of 545 mL. <http://hypertextbook.com/facts/2004/MichaelShmukler.shtml> http://hypertextbook.com/facts/2004/MichaelShmukler.shtml Are you sure that it wasn't 500 g, as that is only 5 g more then 495 g and would not overfill a 450 mL bag? Jerry _____ From: Carleton MacDonald <[email protected]> To: U.S. Metric Association <[email protected]> Sent: Saturday, March 14, 2009 10:30:43 AM Subject: [USMA:43812] Re: 24 hour time One time when I donated blood the bag was put on a metric scale. When the indication on the scale was something like 600 g they took it off, as it was done. Blood is heavier than water, and the bag has a mass too. Carleton Who now is scared to use the word “weight” anywhere From: Jeremiah MacGregor [mailto:[email protected]] Sent: Friday, March 13, 2009 22:05 To: [email protected]; U.S. Metric Association Subject: Re: [USMA:43697] Re: 24 hour time I'll bet the blood they took from you was measured in milliliters but they told you pints. Did you ask them what pint that would be? 473 mL is a pint and 450 mL is what the bag holds. Just think you can become a gallon donor by giving only 3600 mL of blood instead of 3800 mL, a savings to you of 200 mL. Jerry _____ From: Carleton MacDonald <[email protected]> To: U.S. Metric Association <[email protected]> Sent: Wednesday, March 11, 2009 9:12:02 PM Subject: [USMA:43697] Re: 24 hour time The Red Cross came to work a couple of weeks ago for a blood drive. I was the first one in, and went to the booth to have the pre-donation discussion. The worker asked my weight [sic] and I told it to him in kilograms, telling him (truthfully) that I don't know it any other way. (The scale at home shows kg only.) He grumbled and did a somewhat incorrect, though flattering, conversion. And this was a medical person. Dang. Carleton -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Bill Hooper Sent: Tuesday, March 10, 2009 16:41 To: U.S.. Metric Association Subject: [USMA:43655] Re: 24 hour time On Mar 10 , at 2:38 PM, Stephen Mangum wrote: > How does one read 1776-07-04? Easy! One reads it "1776 July 4". What's the problem? For a recent medical problem, I answered questions including my birthdate numerous times. I always said "1935 July 15" and no one ever asked me to clarify that. I don't delude myself; I think most of them wrote "July 15, 1935" but it certainly was not unclear to them the way I said it. I gave my height in centimetres and mass in kilograms, too, by the way.. No problem! Bill Hooper 74 kg body mass* Fernandina Beach, Florida, USA * plus or minus a kilogram or so.
