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 | Experimenting in the LabBrom thymol blue changes color from blue to yellow when you bubble carbon dioxide through it—it's like a "litmus test" for CO2. The only way that brom thymol blue doesn't change color when you bubble gas through it is if that gas doesn't contain significant amounts of carbon dioxide. It's as simple as that. Inhale...put straw in mouth...exhale through mouth...remove straw Inhale...put straw in mouth...exhale through mouth...remove straw Ad infinitum, until it turns yellow. Now, normally the liquid changes color within a couple of minutes, if memory serves. No matter how much I huffed and puffed, however, it wouldn't change. Maybe I had got a "bad batch"? Gave it back to Mr. Giesbrecht, he puffed briefly into it, and it changed color, just like it's supposed to. So he gave me another vial. Sigh. Inhale...put straw in mouth...exhale through mouth...remove straw Inhale...put straw in mouth...exhale through mouth...remove straw Inhale...put straw in mouth...exhale through mouth...Inhale through mouth Gak!! So with me getting a mouthful of brom thymol blue, we had to look up whether it's toxic. This being the early 1980s, we couldn't actually find any definitive literature to state whether it was or not. So we just assumed that it wasn't, and hoped for the best. Really. As they say on the sports field, "Walk it off." Copyright © October, 2008 by Geoff All rights reserved  |