Iz:
Can't help you on the rep questions, I wish I knew myself!
Science though I know a little about
To learn a technology you need to accumulate a certain number of science "beakers" - the number is dependent on some values set in the editor as a base for the tech, plus a factor based on how many civs, that you know, already have the tech - so it's cheaper to research a little behind the AI than to try to lead them.
You accumulate "beakers" by buying them (essentially) through your science %age. That determines what percentage of your gold, calculated separately for each city, goes to buying beakers. The fact that it is done separately for each explains why it seems a little uneven. If you have a total of 100 gold spread across your cities, 50% likely is not 50 gold - it could be more or less depending on how the rounding works - 50% of 5 might be 3, etc...
To complicate things, one gold does not need to give you one "beaker". Libraries etc act to give you proportionally more "beakers" for each gold.
And corruption will reduce your total amount of gold to start with.
An example:
Your citizens in city X are working 6 tiles with a total of 12 gold in them. Your city is only mildly corrupt, so you have 2 lost to waste and 10 usable. (I like easy maths!)
So for each %age*10 you set science to, that city will buy one gold's worth of "beakers". If you have no buildings which affect science, that's all that happens.
If you build a Library, the effect of which IIRC is "science output increased by 50%". Since I
think it rounds up -
someone correct me please if otherwise you'll now get:
10% = 0.1*10 usable = 1 gold for science = 1 * (100+50)% = 1.5 rounds up to 2 beakers
20% will be 3; 30% -> 5; 40% -> 6; etc.
The percentages for all the buildings or wonders just go where the "+50%" is in that equations.
So if the same city had a Library (50%), University (50%), Research Lab (50%), Newton (100%), copernicus (100%) and SETI (100%) your toital bonus would be 450%; in other words each gold devoted to science would earn 5.5 beakers -(100+450)% - in that city.