September 29, 2016 at 03:29AM

Today I Learned: 1) When shipping stuff on dry ice, you apparently need between 5 and 10 lbs of dry ice per day of shipping to keep it cold. 2) Agarose gels don't actually polymerize when they cool -- it's actually a gel of agarose, which is itself a long-chain polysaccharide. Agarose crystal is actually also a gel, sort of. It's a lot of chains cross-linked by hydrogen bonds, at least. Those cross-links stick around in solution, but heating an agarose solution breaks down the hydrogen cross-links, and cooling it down again lets them re-form... but this time, in a large, complete gel. For all the details (and a few details on how polyacrylamide gels work, which *are* polymerized), see http://ift.tt/2dmuaMN, courtesy of Anders Knight. 3) Webcams are considerably cheaper than I expected. You can get cheap USB ones on Amazon for about $20 without really looking hard.