FMF - Friends of Minerals Forum, discussion and message board

[Brian Jackson]

Hi. Does anyone know where I can get hold of a piece of kit that comprises small ball-bearings that allow one to demonstrate crystal dislocation defects. I saw one some years ago but sadly memory fails me to recall who had it and where it was obtained.
Regards
Brian

[Susan Robinson]

Why couldn't you substitute small wood balls, usually found in craft shops instead of the ball bearings?

[Brian Jackson]

I don't actually care much what the material is made of it's just that the one I saw before had tiny 1mm or there abouts ball-bearings and worked very well.

[Minex]

I think thermacole small ballswill be better. Lighter in weight & cheaper also. 1mm to 6mm should suffice the purpose.

[John S. White]

I think that Brian is talking about a closed container with tiny metal balls that you can shake up and while most assume a closest packing arrangement, often some of them are out of arrangement, or there are gaps. I have seen such a thing many, many years ago but I have no idea where it was.

[Duncan Miller]

The best example I have seen is a single layer of uniform small ball bearings, sandwiched between two sheets of clear Lucite/polycarbonate. It demonstrates point defects and edge dislocations. Unfortunately I cannot advise the OP on where to find one, but it should be quite easy to make or have made.

Duncan

[Brian Jackson]

Hi Folks
Many thanks for taking the time to reply. I believe you are right in that I'll have to make it myself even though some, like me, can recall seeing such a piece of kit before.
Ah well another thing to add to the list.
All the best
Brian