Looking for a 3" toy that starts out rocking, ends up spinning

[BroJones]

Does anyone know of a simple small toy, 3" (approx) long and curved on the bottom, such that when you start it rocking, the motion changes (on its own) and it starts to spin...?

It looks a little like a canoe, only about 3" long.

I had a plastic one years ago... can't find it now... Always wondered how angular momentum was conserved as it began to spin..

It would make a nice little gift for some of the grand-kids!

[scottja]

I think it's called a rattleback, One of my physicists co-workers had one years ago. It was his fidget spinner in the day.
https://en.m.wikipedia.org/wiki/Rattleback
Amazon has them.

[David13]

I like this one.
Flips itself over.
dc
https://www.youtube.com/watch?v=ItuAtgv ... %20Reviews

When I was a child my grandfather would carve, from one half of a thread spool a spinning top. He would put a peg or handle in the hole to start the spin. A very old fashioned child's toy.

[BroJones]

That's it! thanks.

Also, this video: https://www.youtube.com/watch?v=1Tx7FgZuV3U&t=141s