Hammer & Chisel

[Matheous-2]

If I strike a steel chisel with a steel hammer causing sparks to fly off - Would these be molecules or atoms that glow with friction?

[woofgang]

neither, its little bits of steel.

[Zacs-Master]

Presumably the steel would be made of ....atoms?

[woofgang]

is steel (not iron) atoms or molecules? In any case I think that the bits that fly off as sparks are bigger than molecules.

[Zacs-Master]

and molecules are made of......you guessed it (or maybe you didn't)....atoms - 2 specifically, which are electrically neutral. Although it can also apply, more loosely, to polyatomic ions.

[woofgang]

indeed ZacM just like everything else is made of molecules which are made of atoms (and loads of space),but just as we call the atoms that are grouped together to make a table "a table", I suggest that the OP's question is more sensibly answered in the "real world" sense by saying that the sparks are, as I said little bits of steel :-)

[Peter Pedant]

The glittery bits are far too large to be molecules or atoms

and are sort of clumps of them - very large numbers of them

If you want to get an idea of atomic size - we were taught that oil on water - when it gets to the iridescent sheen then it is about an atom or two thick

In terms of crystal structure - once you chip off a bit, is it a molecule ?
No
it is a small crystal.

This is / was also covered in the o level chem syllabus.
Sodium chloride - common salt - does it go around as a molecule. No it is always charged Na+ Cl- so it is always wrng to call it a molecule.
Also it doesnt have a mol wt - but ionic wt same number - 58.5 g I think

is that sudduv what you were thinking ?

[mibn2cweus]

The sparks are from the carbon burning in hot steel globules - http://en.wikipedia.org/wiki/Spark_(fire)

[Matheous-2]

Thanks to all.
I kind of expected molecule sized particles, but that was just wishful thinking....

[mibn2cweus]

Essentially what you are seeing is light from photons emitted with the settling of electrons back into the rest orbits of their atoms - http://science.howstuffworks.com/light7.htm