If I hit the home button, does it shut down the app?

[Swift Sketcher]

How do I know which apps are closed and off and which ones are running in the background from hitting the home button? I don't want to leave apps running in the background chewing up battery. Sorry about noob question.

 

[applefanDrew]

If there is audio, location (think gps), or voip (skype) its running in the background. Otherwise, it is saved to memory in the current state, if the app supports the fast app switching api. They can also do task completion in the background and local push, though those don't go in the background for long.


Edit: I forgot to add that just b/c the app is in the tray at the bottom doesn't mean its running, thats just the UI for multitasking.