ever see a daddy longlegs? ever see a rhinoceros, an elephant? humongous legs, very, very thick. why? because as things get scaled up, scaled up and scaled up, it turns out the thickness of the leg doesn't catch up with the bulk of the body. let's see if we can understand these ideas with the simple example. here's a cube. if i make this cube twice as big. how much heavier will it be? are we gonna say, "--what do you mean by twice as big?" this is what i mean, twice as tall, twice as wide and twice as thick. how heavy will it be compared to now? check your neighbors. here's one twice as big, gang. twice as big has twice as much weight? no. everyone who say that, stand up so the rest of us see what you look like. really? the same guy. [laughter] --this guy has a--okay. no, it turned out this can be how much heavier? - four. - eight. eight times. look, 1, 2, 3, 4, 5, 6, oh, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 12 times as heavier, yes. [laughter] just-- i'm counting the same one twice, yeah. but 1 cube 2, 3, 4, 5, 6, 7, then we have to assume that there's one down back there we c

ever see a daddy longlegs? ever see a rhinoceros, an elephant? humongous legs, very, very thick. why? because as things get scaled up, scaled up and scaled up, it turns out the thickness of the leg doesn't catch up with the bulk of the body. let's see if we can understand these ideas with the simple example. here's a cube. if i make this cube twice as big. how much heavier will it be? are we gonna say, "--what do you mean by twice as big?" this is what i mean, twice as tall, twice as wide and twice as thick. how heavy will it be compared to now? check your neighbors. here's one twice as big, gang. twice as big has twice as much weight? no. everyone who say that, stand up so the rest of us see what you look like. really? the same guy. [laughter] --this guy has a--okay. no, it turned out this can be how much heavier? - four. - eight. eight times. look, 1, 2, 3, 4, 5, 6, oh, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 12 times as heavier, yes. [laughter] just-- i'm counting the same one twice, yeah. but 1 cube 2, 3, 4, 5, 6, 7, then we have to assume that there's one down back there we c