Kinda interested what the actual success rate on this workshop was and what strategies the winners tried.
Success rate is ~5-15%. Half of that is people who basically get lucky—the most notable such occasion was someone who did the simplest possible calculation, but dropped a factor of 2 at one point, and that just happened to work perfectly with that day’s ramp setup.
Estimating the ball’s speed from video is the main predictor of success; people who’ve done that have something like a 50% success rate (n=4 IIRC). So people do still fail using that approach—for instance, I had one group take the speed they estimated from the video, and the speed they estimated from the energy calculation, and average them together, basically as a compromise between two people within the group. Another had the general right idea but just didn’t execute very well.
Notably, the ball does consistently land in the same spot, so if one executes the right strategy well then basically-zero luck is required.
I expected the point of the exercise to be showing what it looks like when you’re exposed to reality’s raw messiness unprotected, even in an experimental setup as conceptually simple and well-understood as that.
for instance, I had one group take the speed they estimated from the video, and the speed they estimated from the energy calculation, and average them together, basically as a compromise between two people within the group
If you only care about betting odds, then feel free to average together mutually incompatible distributions reflecting mutually exclusive world-models. If you care about planning then you actually have to decide which model is right or else plan carefully for either outcome.
...only four people out of how many estimated the speed from the video? Here I was chastising myself for thinking of essentially Robert’s approach second (after about a minute or two) instead of immediately, and am surprised so few measured speed at all.
Tangentially, I’m not sure if I’d have thought of ramp flexibility even after observing a different speed than expected from energy conservation—I might have just chalked it up to rotation or friction. But to not measuring the velocity...!
Once in high-school I successfully predicted from theory alone the height required for a free falling toilet paper roll to hit the ground at the same time as a roll that has a sheet held to a wall, but even just my chance of a math error is high enough that I wouldn’t trust it. And I consider that more effort than measuring speed, despite being comfortable with the math.
Success rate is ~5-15%. Half of that is people who basically get lucky—the most notable such occasion was someone who did the simplest possible calculation, but dropped a factor of 2 at one point, and that just happened to work perfectly with that day’s ramp setup.
Estimating the ball’s speed from video is the main predictor of success; people who’ve done that have something like a 50% success rate (n=4 IIRC). So people do still fail using that approach—for instance, I had one group take the speed they estimated from the video, and the speed they estimated from the energy calculation, and average them together, basically as a compromise between two people within the group. Another had the general right idea but just didn’t execute very well.
Notably, the ball does consistently land in the same spot, so if one executes the right strategy well then basically-zero luck is required.
Yup, that is indeed the point.
… Which is a whole different lesson:
...only four people out of how many estimated the speed from the video? Here I was chastising myself for thinking of essentially Robert’s approach second (after about a minute or two) instead of immediately, and am surprised so few measured speed at all.
Tangentially, I’m not sure if I’d have thought of ramp flexibility even after observing a different speed than expected from energy conservation—I might have just chalked it up to rotation or friction. But to not measuring the velocity...!
Once in high-school I successfully predicted from theory alone the height required for a free falling toilet paper roll to hit the ground at the same time as a roll that has a sheet held to a wall, but even just my chance of a math error is high enough that I wouldn’t trust it. And I consider that more effort than measuring speed, despite being comfortable with the math.