Lichtenberg kept Sudelbücherscrap books (n.)A merchant's rough daybook, kept before the clean ledger. Lichtenberg thought scholars should keep some too, so he did, filling them with rough, casual, fun experiments for 35 years.. I started one as a kid and still add to it in college when I get the time. There is no particular theme here, but it's all in my immediate environment.

• Made piezoresistive, self-sensing concrete in my friend's basement (during my summer in Philly).
• Built a 4.5 km road to my school in rural India out of waste plastic, depolymerized in a sub-$10k catalytic pyrolysis reactor.
• Built an eddy-current brakeRaising the load from 1 N to 9 N spun the disk faster and more than doubled the braking, from 2.5 to 6.2 rad s⁻². for my bicycle that worked at high speeds but not low.
• Destroyed azo dyes from the lake next to my horse's stable (Pune, India) with sunlight, copper and peroxide (a photo-Fenton reactionSunlight destroyed 93% of the dye in the most dilute sample, but only 21% in the most concentrated one.).
• Ran complexometric titrationsKale washed at room temperature kept 81% of its calcium. Boiled for three minutes, it kept 4%. on my kale salads to see how much calcium cooking steals. (Nota bene, I had a broken collarbone from a horse fall at the time.)