I took a home blood test today, and it included a reusable heat pack. These things have been around since the 1970s, but this was the first time I've used one. It's a plastic pouch with liquid inside and a small metal disc stamped with many dents. — Read the rest

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A 5-milliliter ampoule of the world's most precise water sells for $159 — about $120,000 a gallon, Signore Galilei writes. It is Vienna Standard Mean Ocean Water (VSMOW), and labs buy it because water's freezing point varies based on its elemental isotopes. — Read the rest

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