Neat. Makes me wonder how long it would spin in the other extreme, surrounded by air but with zero friction. In my naive mind, I imagine it'd go considerably longer. And of course with zero air and zero friction it'd go on indefinitely.

Air resistance vs. friction. Who will win out?!

cool

Cool indeed.

Not directly related, but reminds me of something cool about vacuum: The air above us , the atmosphere, has weight such that it presses on everything from all directions (even "up") at 14.7 pounds per square inch. The effects of this aren't noticed, for example, when a dry piece of glass is placed on glass table. The air pressing down on the glass is equally counteracted by the air molecules under the glass pressing up. If, however, you wet the glass and press it onto the glass table, the counteracting air pressure from below is removed - the air pressure is now applied only to the top of the glass, so the full 14.7 pounds per square inch presses down and it's difficult to break the bond. Same reason suction cups work.

TOPS I N SPAAAAAACE

That space video from @oohlalasassoon tends to proves you right -- there there is no friction on the pivot point, but the top is still surrounded by air. It isn't clear exactly how long it would take before the air resistance would stop the spin, but it seems like it would be quite a bit longer (orders? of magnitude) even than the top in a vacuum.

I wouldn't have called it that way; the pivot point is so small that it has an very small surface area. And the vacuum chamber would leave that variable close to constant, but still resulted in a lot longer spin time -- so the air resistance (friction with the air instead of friction with the pivot point) clearly does have an effect.

Interesting stuff!

I wonder if he would have gotten the same result if he'd spun a top with a smooth shell/continuous cross section?

What about a superconducting magnet being used to suspend a top, both in a vacuum and not?

Similar to this - which is smooth shell/continuous cross section but sadly very short in duration.

It depends a huge amount on the shape of the top. The one in the original video has a lot of bits sticking out around in to catch the air and cause drag. The one in the space video doesn't, it's a smooth circular shape so its drag will be a lot less.

Drag and friction are just two forces acting on an object in motion. If they were equal forces surely the top would spin for twice as long if either one was removed? The fact that it spins for a lot, lot longer once drag is removed makes me think that in the case of that particular top the air resistance is a much higher force than the friction with the table.

I wonder how fast the top would go out, if it were on fire when he started the vaccuum

I wonder...if I take viagra....in a vacuum...in space, could I spin like a top?

Air is friction, same as the spinning surface. I think you mean air friction versus friction from the spinning surface.

Assuming so, consider that without a surface, that top could slow down until it was at rest, but with a surface, the moment it gets below a certain speed, it wobbles and hits the surface and the surface contributes significantly to the slowing down. To truly compare the friction of the surface with the friction of the air, you'd have to factor out the force of the surface stopping the top.

This means, either eliminating the possibility of the top falling in the zero-air method, or only measuring the time until the top falls below the wobble speed threshold. The latter seems easier.