Question

a) When we put our ear to a railway line, we can hear the sound of an approaching train even when the train is far off but its sound cannot be heard through the air. Why? 

b) How could you convince a small child that when you speak, it is not necessary for air to travel from your mouth to the ear of a listener?

Answer 1

a) We can hear the sound of an approaching train by putting our ear to a railway line because the sound waves travel faster through the steel than the air. 

b) It is not necessary that air should travel from your mouth to the ear of a listener because sound waves travel through the layers of the air such that there are vibrations that are created which makes the sound to travel from mouth to ears through these layers.