Common problems

listen and hear

Many students use listen and hear interchangably. However, there is an important difference between them. Listening describes...
an intentional activity. When you are listening, you are actively trying to hear something.
In contrast, hearing is something that happens without any intentional effort. You can hear something even when you don't want to hear it and don't try to hear it.
The sentences below contain both listen and hear and show the contrast:

• I listened outside the door, but I couldn't hear what they were saying inside. [Note that even if you listen, you don't always hear what you are trying to hear.]
• His story was so long and boring that I stopped listening, until suddenly I heard my name. [Note that even if you are not listening, you might hear something.]

Finally listen is often used with to.
In the examples below,taken from the Cambridge Advanced Learner's Dictionary, listen or listen to cannot be replaced by hear:

• What kind of music do you listen to?
• She does all the talking - I just sit and listen.
• You haven't listened to a word I've said!
• We listened in silence as the names of the dead were read out.
• Listen, we really need to sort out our insurance claim this weekend.
• Listen to this! You can win a holiday for two in the south of France just by answering three simple questions.

Likewise, in the examples below, hear cannot be replaced by listen, because hear is describing something that a person cannot control/

• She heard a noise outside.
• My grandfather is getting old and can't hear very well.
• You'll have to speak up, I can't hear you.

HOWEVER, there are a few cases in which hear is used to mean something very close to listen to. In the examples below, listen to could replace hear.

• I heard a really interesting programme on the radio this morning.
• I heard the orchestra play at Carnegie Hall last summer.
• An audience gathered to hear him speak.

Why is hear used instead of listen to in these cases? Maybe because the emphasis in each case is on the contents of what is hear rather than on the activity of listening.




Source:
http://www.f.waseda.jp/vicky/students/help/mistakes/listen-hear.html