word-wrap:break-word not working,white-space:normal works

What's the differences between word-wrap and white-space?Recently one of my client need me to fix his premimum theme which can't show portfolio description in the portfolio.It's wrapped by <span> tag,first I thought add word-wrap:break-word; to the span tag can slove this problem,but not working at all.After a hard search,I fianlly add white-space:normal; to span tag and slove this problem successfully,what's the differences betweent them?

It is good that you have solved it yourself. And we can do it if we have the considerable amount of knowledge about our expertise.