Remember how the professors made a big deal about Harry not discussing his discovery about potions?
Perhaps school manuals are picked to contain only potions with magic ingredients, as a misdirection for people not wise enough (students) to try to figure out the "well-known secret", the same way Harry was at first.
But Harry's potion didn't release a lot of magic, it only released light (note that in the coin example, it was the non-magical coin that furnished the "heat"), so probably Harry used a bit of magic (like in Potions class) to "rearrange" the light without need of magical ingredients.
(Also, why wouldn't "wizard hair" count as a magical ingredient?)
(The HPMOR discussion thread after this one is here.)
This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. There haven't been any chapters recently, but it looks like there are a bunch in the pipeline and the old thread is nearing 700 comments. The latest chapter as of 7th March 2012 is Ch. 77.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author's Notes.
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven, eight, nine.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: