Physics and Language

Question

Convection currents occur only in fluids but not in solids. This is because convection involves the bulk movement of fluids which carry heat energy due to a change in density.

Alright, what does the second statement mean?

1.) Bulk movement of fluids is the result of a change in density.

Or is it

2.) The fluids carry heat energy because of a change in density.

Thank you.

Answer 1

Grammatically, the second version is correct.  (Not being a scientist, I have no idea if that's the case in fact.)  

Answer 2

1 is absolutely correct. This question is more about the meaning of the statement as opposed to grammar.