Signals vs Cues, Electric Cars, and Fire... In Spaaaaace!

Today I Learned:
1) In sociobiology (in particular the study of social insects) the term "signal" means something an organism does, and is evolutionarily selected to do, in order to intentionally tell others about some condition; the term "cue", in contrast, denotes something that an organism can use to infer some condition, but isn't selected for to act as communication. For example, a wounded person screaming for help is a signal, which another person can pick up on to know that somebody's in trouble; a person bleeding all over everything is a cue, which another person can pick up on to know that somebody's in trouble. Both are effective communication, but the signal is selected for on the basis of its information-bearing nature and the cue isn't. (Another example, an ant changing its behavior in response to a pheromone indicating the presence of food is picking up on a signal, while an ant changing its behavior in response to lower food availability in the colony is picking up on a cue).

2) Chevrolet sells a fully-electric small car (the Chevrolet Spark) for around $25,500 -- which becomes a net $17,000 after a US tax credit, at least as long as total Spark sales remain below 200,000 cars. That's more than *I* can afford right now, but I'm surprised how cheap it is. The Spark has an 80-mile/charge range, and takes between 7 and 20 hours to charge depending on what voltage you use to charge it. It has decent overall ratings, coming in at the #10 Affordable Subcompact Car in US News & World Report rankings.

I also learned today that electric vehicles don't, in general, need oil changes... because they don't need oil... because they have shockingly simple engines.

For a fun little anecdotal review of electric car ownership, see: http://ift.tt/1FRYwJf

Thanks to Chigozie Nri for pointing me down a rabbit hold of fascinating internet posts on electric cars.

3) Flammability works differently in space. NASA recently sent a burn-box to the ISS, in which they tried burning a bunch of common spacecraft materials. It turns out that the burning properties of some materials are radically different in low-G. For instance, a flame-retardant cotton-fiberglass blend similar to the stuff used in a lot of astronaut's cloths burns quite well in space. Also, the usual methods of putting out fires don't necessarily work -- spraying on flame-retardant foam, for example, can end up just spewing fire everywhere and making the situation worse.