Aluminium Foil Ball Challenge - F-J's Physics - Video 193

Having seen others try the Aluminium Foil Ball Challenge I thought I would give it a go. Not too difficult and a pleasing end result but on and off it took me two years to complete! Let's see how I did it.
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[@AnthonyFrancisJones]

Please consider supporting my work by buying me a coffee at www.buymeacoffee.com/francisjonesa Helps me buy bits and pieces to make these videos! Very many thanks, F-J

[@AnthonyFrancisJones]

All a bit of fun and managed to get a little bit of physics into it! Thanks as ever for watching.

[@markgreco1962]

Thanks Anthony

[@AnthonyFrancisJones]

Pleasure Mark and thanks for supporting the channel as ever!

[@anthonyjones5711]

This has given me an idea how to make something (not a ball) I've been thinking about for some time, foil will work but I think I will be using a hydraulic press not a hammer.

[@AnthonyFrancisJones]

Look forward to hearing more...!

[@airfriedquadsbw]

I can say from experience making layers like wrapping it is not the way. The inner part will press against the outer layers. The densities are not the same internally. You end up with a ball in a shell. It is best to bunch all the foil together at once, in a random way to distribute the impacts into the whole ball, not just the shell. If you do end up with a rattling ball inside it can still be ok, maybe a real good way, but a smaller ball. Open the shell and work on the inner ball. You will find if it rattles and you open it, the ball inside is very symmetrical and dense. The center ball was started with random compaction. And at some point you start wrapping. The center ball is the random part. So to use all the foil and not get a shell and rattle start with all the foil unrolled. And bunch it all up at once. Keep a sphere shape as possible, but it is not that critical since hammering it to get it dense will achieve a ball from a shape that seems to lumpy to start. A good test for density is "will it float in water?" If you get it to sink your doing pretty good. It isnt easy to do. Using the bottom of a tin can to hold the ball when hammering, or something like that will help a bunch. And as a hammer I use a 2 inch steel ball. Or a 1 inch on a smaller sphere. Polishing, I never sanded at all, and never used any polishing material. I simply rub the steel on the sphere and end up with a very smooth sphere with a near mirror surface. I found an aluminum geer that is very smooth and using it like sand paper it gets an even smoother surface.

[@AnthonyFrancisJones]

Thanks, yes, I see your point about random scrunching and then wrapping. It was all a bit of fun really. As far as sinking or floating in water, this one would definitely sink as it was almost 2000kg/m^3 which is twice the density of water but only about 2/3rds that of aluminium. Glad you had lots of success with yours. Be tempting to try brass foil or even a lead one!

[@airfriedquadsbw]

@AnthonyFrancisJones I finished an aluminum one with s layer of copper foil. I like the look of it.

[@fburton8]

Not _quite_ as spherical as kzbin.info/www/bejne/kH6lqnxqqJJ3Y7s (!) but pretty good nonetheless. It would be interesting to see what the material is like in cross section close up, e.g. with a scanning electron microscope. A good proportion of it must still be air with a bit of oxide too, but I wonder how it's distributed.

[@AnthonyFrancisJones]

Yes, I remember that sphere when it was discussed in Physics World a few years ago. Not quite that close indeed! I really would not want to cut it in half but would be interesting to see what it looks like. Ultrasound would just produce an mess of an image I think. Adam Savage did a good job with the water jet cutting kzbin.info/www/bejne/pZ-9dXSBf9ZpsJY I really feel that, whilst there must be lots of voids, dirt/oxide etc. the layers may well have got close enough to form metallic bonds. It was a fun project regardless and thanks as ever for your interesting observations. Do keep them coming!

[@airfriedquadsbw]

In my comment I mention the layers of density and how I avoided those layers, and how I achieved layers unintentionally. And made a rattle that I opened and found a very nice ball inside. What a Hobbie, haha.