Inside The Home – 2.1

Pure Water

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Man Runs Car on Pure Water and Sun

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Why does 1mL of pure water weigh exactly 1gram?

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I thought the MSI unit lengths were now based on a particular wavelength of light. So why the perfect correlation between 1000 cubic mm and 1.000g of pure water? Can't be luck... can it?

No, the equivalence between ml, cm3 and g is by definition. As you say, 1ml of water weighs exactly 1g, and takes up exactly 1cm3. This is because they were originally defined as such.

The wavelength of light comes into play because, having taken these as given, the definitions of a second and a metre have been redefined as using a certain wavelength of light, and a certain mass of caesium, that ends up with the above values. The choice was arbitrary, but don't forget that litres and kilogrammes were first defined shortly after the French revolution, many years before we could measure the speed of light (or even had any idea that it moved at all).

Athena® Home and Office Bottled Water Delivery Sales Bolster Fight Against Breast Cancer

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One of the newest brands in the DS Waters® family of home and office bottled water delivery generates $300,000 to fight breast cancer.Atlanta, GA (PRWEB) July 15, 2011 Athena®, one of the newest brands of DS Waters home and office bottled water delivery, is generating funds for breast cancer awareness, education and research. DS Waters of America, Inc. CEO Dillon Schickli presented a check for ...