Wednesday, 19 June 2013

10:31 – Yesterday, I finally got around to ordering some stuff from Costco that had been on my to-do list for a week: a CyberPower PC, a Brother multi-function printer, and a DeLonghi dehumidifier. The dehumidifier kills two birds. It’ll make it a lot more comfortable to work in the unfinished area of the basement, and it’ll produce several gallons a day of distilled water for making up chemicals.

I’m debating with myself about introducing an AP Chemistry kit for autumn semester in 2014. I’d actually considered doing it for 2012, but it just wasn’t worth the effort. College Board was in the midst of revamping AP Chemistry for 2013, so a 2012 kit would have been obsolete after a year. They did the same thing with AP Biology last year, shifting from procedural labs to “the Big Picture” and “inquiry-based” labs. That’s fine for a classroom environment with a qualified AP chemistry or biology teacher directing things and keeping students from going off the tracks, but it doesn’t translate well to a homeschool environment.

The other problem with the current AP Chemistry labs is that they’re very equipment intensive. The $20 milligram balance I mentioned yesterday solves one of the problems, but the current AP labs as specified require quite a bit of other expensive equipment, most notably a decent pH meter and at least a colorimeter if not a spectrophotometer. Now, you can buy a pH meter with 0.1 pH resolution for $25 or $30, but the problem is that these cheap meters are notorious for requiring constant recalibration. Decent pH meters with 0.01 pH resolution are available for $75 to $150, but that’s not a minor expense for many homeschoolers, particularly for just one instrument. The real show-stopper is the colorimeter/spectrophotometer, which is used heavily in AP chemistry. Typical dedicated 3- or 4-color colorimeters cost $500 to $800 or more.

My first thought was that we should open-source this hardware, kind of like my $50 Dremel ultracentrifuge, which does pretty much the same thing as a commercial $5,000 ultracentrifuge. But only a tiny percentage of homeschoolers would be willing to “roll their own”. So my second thought was modular hardware designed for education, such as the product line from Vernier. You start with an interface, the simplest of which is a $61 unit that simply connects sensors to a USB port on your computer. You then install logging software, which ranges from free for a basic package to $200+ for their high-end package. You then add sensors, such as a $79 pH sensor, a $115 colorimeter sensor, a $29 temperature sensor, and so on. It’s still not cheap, but it’s a lot cheaper than buying dedicated units for each function. I’ll have to think about this for a while before I decide what, if anything, to do.

Oh, yeah. That iodine that I ordered on eBay showed up yesterday, or at least I assume that’s what’s in the small box I received from an address in the Ukraine. The small box weighs 320 grams, so I suspect there actually is the 250 g of iodine I ordered in there. Geez, that probably puts me on yet another list.