How do bobble head dolls work?

Years ago, before bobble head dolls were popular (even before those ESPN commercials with a bobble head player for each team), I pulled the head off of one for curiosity. It was simply a quasi-spheroidic head balanced on mini-pole that jutted up out of the doll’s neck. The head basically just rocked on this nib that stuck up inside of it. Since then, I’ve assumed that booble heads still work on this same basic principal.

But now I see people pounding the top of the heads to get them to bobble as if there is a spring inside of the head. But it doesn’t appear as if the head is going up and down, it just bobbles midly with a :rolleyes: look on its face.

Have they changed the general structure of booble heads in the past 20 years? Or are these people who pound the top of the head just :confused: morons?

On a side note, as I was trying to find my answer through google, I came across an excellent bobble head doll: booble head Football Jesus.

More to the point, where did these things come from and why are they suddenly so damn popular??? And when will they go away???

Spring. My 5-year-old son got a bobble-head free at a pro basketball game and soon disconnected the head. In fixing it for him I had to glue the spring in the head to the neck nubbin.

Yes, it’s a spring. You can tell how tight the spring is by the way the head bounces.

I think they started making a comeback with the ESPN baseball commercials in the mid-90’s.