This person is listening to music while he shows his friend something on his phone. 

This person needs a way to 

This person is listening to music with her friend.

These people need a way to have music flow in through both ears so they can both fully experience the music. 

Verplank Diagram (for above picture)

This person is listening to music while getting ready to ride his bike. 

This person needs a way to listen to music and be aware of his surroundings while biking.

This person is listening to music while doing his homework outside.

This person needs a way to listen to music without being disturbed by the loud sounds outside.

This person is listening to music while driving.

This person needs a way to listen to his/her loud music without disturbing others while he/she drives by.