4 ms·
Here’s one nice such surprise to amaze any kid (or a date, if they’re of the right mold): get a ruler or a uniform stick, balance it on your index fingers by pl
by Jun8 3y ago
Here’s one nice such surprise to amaze any kid (or a date, if they’re of the right mold): get a ruler or a uniform stick, balance it on your index fingers by placing them randomly along the length. Then start moving your fingers together. They’ll always meet at the center (center of mass)! Your fingers take turns moving as if by magic. Your audience will first think that you’re purposefully moving them, so next let them do it.
- bhattid 3y agoI like this one! I was curious what the margin of error for this was (I'm conjecturing the sum of widths of the fingers touching the stick), so I tried this out, but with a pencil instead of a stick. I was consistently getting just off-center, so I was thinking maybe the 'surprise' wasn't consistent, until I realized the end of the pencil (metal + eraser) is probably denser than the wood and shifts the center of mass to exactly where my fingers ended up. :)
- bhattid 3y agoPlaying around a bit, I think the margin of error is probably the average of the sum of widths (so the width of a finger, if they're equal).
- belter 3y agoNext go for the “Light as a feather”: https://blog.donders.ru.nl/?p=12234&lang=en https://blog.donders.ru.nl/?p=12234&lang=en
- rainbowzootsuit 3y agoI got this from Mr Wizard as a kid and use it infrequently but regularly when making things and needing to split a piece of material in two. I know it's the CG and not the geometric center, but is often close enough with reasonably uniform material.