The children surprised to hear his recorded voice because they compare it with their own that they usually hear and perceive that it is not the same. Many years ago recording your voice was possible thanks to the Walkman who could record! and to the mussettes in which the sound was stored in analog. At present, kids can use any mobile device to record in digital format, which can also be shared quickly, through social networks and the Internet. It is interesting that they do the exercise and see their reactions. The reasons why the sounds are different have been found in Microsiervos and explains them Greg Foot in the video below called Why does your voice sound different on a recording? (Why does the voice sound different in a recording?)
And it is that when we hear our own voice the sound that we perceive as vibrations through the air is mixed with the vibrations that our vocal cords transmit to our skull generating a mix that has a lower tone than our real voice. Therefore our voice sounds so weird, generally more acute, when we hear it recorded.
So kids can learn this difference and take advantage of it to sing, emphasize and above all vocalize when speaking or reading. It is very interesting that children record their voice and practice speaking in public to improve their communication skills.
