Posted by alexandra_k on September 4, 2014, at 20:35:49
In reply to Re: osmosis question, posted by ClearSkies on September 4, 2014, at 20:05:15
the farraday cage thing was a lateral leap.
it was related only because it was something else i was having trouble with. for one of the assignments we had to say whether there was a current inside the wire and what direction the current was travelling in.
and i thought the wire would make a farraday cage since we learned that farraday cages can be solid or hollow. round or... any shape. that the electrons spread out across the surface to minimise repulsions in such a way that the net charge inside a farraday cage is zero...
so i figured that the current must travel along the surface of the wire and not inside it.
which made some kinda sense because i faintly remembered something about neurons carrying charge along their surface.. (anyway... i think they turn out to be really rather different so i best just forget about that for now)... and... anyway... it turns out that current is conducted along the inside of a wire. and apparently current isn't really about the flow of electrons, anyway, since electrons don't move very fast really and they are moving in the opposite direction anyway...
and it is all very confusing to me.
osmosis...
i only need to remember about cells and interstital fluids... about how water gets shunted about as a consequence of solutes being shunted about. about how membranes are selectively permeable to solutes... about how it takes energy for cells to maintain concentrations of solutes that are different from the external environment. how water will follow the highest concentrations of solutes... how lots of solutes in cells results in lots of water in cells results in bloating of cells results in osmotic pressure accumulating inside cells results in them bursting. that's all...
i can't tell how much i need to learn better focus... or how much it is useful to think, sometimes. probably... focus for now. i don't know.
i don't suppose i'm doing very badly, actually. it is just that i'm used to doing really very well. and i'm certainly not doing that. grump.
with the farraday cage thing... i did start to wonder... whether we were supposed to say something about vectors... that the wire was a farraday cage in the width dimension but that the current travelled lenthways between the voltage differences ? then i started to draw that... and then i realised that probably that just didn't make any sense.
poster:alexandra_k
thread:1070688
URL: http://www.dr-bob.org/babble/social/20140828/msgs/1070784.html