A few thoughts I had while driving today:
<while listening to Hairspray, the movie soundtrack> The speed of sound? At atmospheric conditions, that is 343 m/s. But of course at lower temperatures, that would be much lower. Next time I fly, I should find out the airplane's external temperature so I can figure out how fast the the airplane would need to travel in those conditions to be traveling at sonic speeds.
<while driving on extremely wet roads> I always assumed that speed limits were something designated by the engineers who designed the roads, accounting for a safety factor. i.e. a speed limit of 65 mph would actually correlate to safe driving at speeds up to about 90 mph. However, now that I think about it, I wonder why I ever assumed engineers had any say in this. Isn't it lawmakers who set speed limits? Do they understand/know the parameters the roads were designed for?