In OS X there is a lock icon in the lower right of the Get Info screen. What is this icon called? What does clicking this icon do?
I am running on an account with administrator access. I have the ability to change permissions of some folders (one on my desktop) but not others (one in the Applications folder). The "lock" is locked in both cases. When I tried to Terminal → su → chmod the folder in Applications I still had no luck, until I pressed the 'lock' button.