HPMoR 113: A draft of solution
This post is about fanfic Harry Potter and the Methods of Rationality by Eliezer Yudkowsky. If you haven't read it, I strongly recommend at least trying it. In my opinion it beats the original, at least in some respects.
Here's my solution for the problem stated in the end of Ch. 113
Method: partial transfiguration. I am going to assume that the limit on the amount of matter Harry can transfigure is ~1 l per minute.
The key elements of the device Harry has to transfigure are based on a pen gun - without any features concealing its nature, maybe with sturdier barrel instead.
Trigger mechanism: can use electricity or chemistry (some chemicals that would react explosively right after the transfiguration is complete).
Bullets: 1) whichever should be the deadliest of "standard" bullets when fired from a pen gun from a distance of 0.1 to 2.5 m (expanding bullets?), or 2) a steel rod surrounded by payload with steel conic cap and base to penetrate skull and protect the payload, respectively. Payload being potassium.
40+ such guns should be created, connected with a thin wire to make them a single object. (The same wire might be used to conduct current from a power source.) One for each Death Eater, several for Voldemort (the design does not seem entirely reliable but if Voldemort and the vast majority of the Death Eaters are dead, the rest might be less eager to kill Harry).
Total volume should be below 1 l, and if Harry cannot do it in a minute he can start telling one of his secrets without spoiling the surprise.
So the most important remaining question is the source of partial transfiguration.
A. Air. I don't think source being a solid object was mentioned as a constraint on partial transfiguration. Certainly Harry's thoughts about the concept of "material object" being feature of map, not of territory imply that transfiguring some air should be possible. It is also plausible that Harry had previously come up with the idea (maybe when he was cleaning troll's fluids from his wand) and tested it.
B. Earth. If air is not a valid source of partial transfiguration, Harry can come up with the rest of a plan, figure out that he needs to touch ground with his wand and then legitimately say something like "I need to sssit" - if it is accompanied by swaying Voldemort might not see the need to ask why.
(If air can indeed be source of transfiguration, then the "pen" guns should be placed above the enemies' heads facing down, ends of the barrels weighed by lead to make sure they shoot in right direction. For Voldemort, a few additional barrels aiming from different directions can be used, including some not aimed for his head. Just in case :) )
Here's my solution for the problem stated in the end of Ch. 113
Method: partial transfiguration. I am going to assume that the limit on the amount of matter Harry can transfigure is ~1 l per minute.
The key elements of the device Harry has to transfigure are based on a pen gun - without any features concealing its nature, maybe with sturdier barrel instead.
Trigger mechanism: can use electricity or chemistry (some chemicals that would react explosively right after the transfiguration is complete).
Bullets: 1) whichever should be the deadliest of "standard" bullets when fired from a pen gun from a distance of 0.1 to 2.5 m (expanding bullets?), or 2) a steel rod surrounded by payload with steel conic cap and base to penetrate skull and protect the payload, respectively. Payload being potassium.
40+ such guns should be created, connected with a thin wire to make them a single object. (The same wire might be used to conduct current from a power source.) One for each Death Eater, several for Voldemort (the design does not seem entirely reliable but if Voldemort and the vast majority of the Death Eaters are dead, the rest might be less eager to kill Harry).
Total volume should be below 1 l, and if Harry cannot do it in a minute he can start telling one of his secrets without spoiling the surprise.
So the most important remaining question is the source of partial transfiguration.
A. Air. I don't think source being a solid object was mentioned as a constraint on partial transfiguration. Certainly Harry's thoughts about the concept of "material object" being feature of map, not of territory imply that transfiguring some air should be possible. It is also plausible that Harry had previously come up with the idea (maybe when he was cleaning troll's fluids from his wand) and tested it.
B. Earth. If air is not a valid source of partial transfiguration, Harry can come up with the rest of a plan, figure out that he needs to touch ground with his wand and then legitimately say something like "I need to sssit" - if it is accompanied by swaying Voldemort might not see the need to ask why.
(If air can indeed be source of transfiguration, then the "pen" guns should be placed above the enemies' heads facing down, ends of the barrels weighed by lead to make sure they shoot in right direction. For Voldemort, a few additional barrels aiming from different directions can be used, including some not aimed for his head. Just in case :) )