"Matty F" wrote in message
...
On Jul 5, 12:47 pm, Roger Dewhurst wrote:
Matty F wrote:
On Jul 4, 11:55 am, Roger Dewhurst wrote:

Forget the billiard balls and go looking for the largest ball bearing
available. They might come from some very heavy machinery, not
necessarily with wheels! Steel is much more elastic than billiard
ball
material. I mean elastic in the physical sense not like rubber.

I've already considered steel balls. If they were the size of billiard
balls or bigger, they would be very heavy and would squash the fingers
of the unwary and OSH would be nasty to me.
I have considered steel rods in wooden balls. I may go back to that
seeing as the billiard balls are going to be more expensive than I
thought.

This thing works because and only because of the elastic property of
steel.

Where were you when I last discussed this? You mean my billiard balls
won't work now that I bought them?
However I just tested them. They seem to work fine!


Putting "newton's cradle" into youtube brought up
http://www.youtube.com/watch?v=mFNe_pFZrsA
and
http://www.youtube.com/user/PaulOrse.../2/ohC9u8M7ZiQ

The guy has a website
http://www.orselli.net/

However I liked
http://www.youtube.com/watch?v=Lkn6fMn9eqU

Cheers

Adam