If i took a piece of hard granite, heated it and placed it in a dish of cold water, would the rock crumble and experience weathering?

it might fracture due to thermal contraction but it wouldn't 'crumble' infact, it probably wouldn't fracture unless you done it a few hundred times.

 

i don't know if you could still call it weathering though as this wouldn't really occur in nature. a common weathering process on rocks that does cause them to crumble(albeit slowly) is when there is a crack in the rock that fills with water, freezes, thaws and freezes in a cycle. that process can reduce any rock to dust.

ok, cheers.