HEAR vs LISTEN

Listen is used to talk about or describe sounds that are being made around you and which you are making an active effort to focus on. For example:

• Did you listen to the news last night on television?
• She was listening to music on her iPod when I walked in.
• Mike listened to his teacher and then repeated what she had said.
• ‘Just listen to yourself! You talk such rubbish!’, she said angrily.

Note that ‘listen‘ is nearly always followed by ‘to‘ - you listen to some sound.
Just to repeat an important point; listening is active - that is you are making an active effort to listen to the sound.
Hear is used for sounds that come to our ears, but we do not, unlike listen, need to be actively engaged in trying to listen to the sound - it can just come to your ears! For example:

• Mike heard a bang in the night which woke him up.
• She heard someone screaming and called the police.
• I heard a loud explosion and then the building collapsed.

Note that ‘hear’ is not followed by ‘to’. But, to make it a little more complicated let’s look at this conversation:

• ‘Did you hear what I said’, asked John’s father.
• ‘No, I wasn’t listening‘, replied John.
• ‘Well, if you don’t listen you will never hear what I am telling you!’.

Now, that last sentence seems a little confused but also shows cleary how the two verbs are used - in this case, if John does not make an active effort to listen he will not hear his father’s advice (even if he may have heard sounds his father was making!)
Where hear and listen may seem very close is when you hear something like:

• Did you hear about Jane? She got married!
• I heard about the accident but I didn’t see it.

This is when information is passed to you from another source without you necessarily seeking it - in this case note that ‘hear’ is followed by ‘about’ - ‘to hear about’ something, someone or some action or event.
So, you can hear something without wanting to, but you can only listen to something intentionally.