Why do we bring our hands close to the mouth while shouting across to someone far away?

Friends, How you call any person who is away from you…not too far away, just you can look him but cannot talk him. You simply use a fantastic trick, you shout for that person bringing your hands near your mouth likewise as in photo.

Do you know the scientific reason behind this trick? Well, sound can travel in any direction with same speed but when you shout bringing your hand near mouth, the sound’s direction is directed in a particular direction so the sound can travel longer distance and the possibility of listening the sound by the person is increased.