Talk:Betz mystery sphere

Continuity
No mention of what happened to it after 1974?? - Joaquin89uy (talk) 14:56, 8 January 2024 (UTC)

Ball mass
If the ball is made from steel (assuming 7.5kg per liter) why for 10cm radius there's only 10kg? Mass for 10cm radius is over 31.4kg (4/3*PI*1000*7.5). Ok, maybe ball was empty for some reason but then, how it was made? 87.205.194.100 (talk) 20:11, 28 January 2024 (UTC)


 * Hollow bearing balls are usually made in halves, and then welded together. A good weld will complete disappear when you polish it, and ball bearings are often pretty heavily polished.
 * I believe there are also newer processes where the steel can somehow be formed around a plastic core. I don't quite understand how that works. I don't think that would have been available in the 1970s anyway.
 * The "reason" for making them hollow is, of course, weight. As you point out, large solid steel spheres would be quite heavy, so above a certain size, it's common to make them hollow. ApLundell (talk) 03:54, 29 January 2024 (UTC)