I stand corrected. I misconstrued something.

What I was trying to say was correct - just a bad example; magnesium was better.

I guess my Mr. Wizard joke wasn't too far off - just found the same experiment in this Canadian High School Science experiment.
http://www.edu.pe.ca/agriculture/nutchems.pdf

and an Indiana University chemistry course
http://courses.chem.indiana.edu/c118...structions.pdf

and here (scroll down to page 4)
http://us.boehringer-ingelheim.com/c...nts_051810.pdf

Filings? Not exactly. It's iron, but several pages refer to it as "Food grade iron powder".
http://www.flinnsci.com/Documents/newsPDFs/91603.pdf

This phenomenon seems to be all over the place, and for a long time. IMO these recent(?) vids are just another case of old news making a big sensationalist splash.

Doc