Task N. 7 - What is the role of the sound in that videos?

Watch the videos. Some of them are about the variability of sound, using sound. Nature ones, Dziga Vertov´s ones are trying to use the sound in the complementarity to picture. Please select one or two and try to compare the role of sound in the videos. Or if you choose Dziga Vertov´s experiments, try to espres what is the aim of them, how there radio experiments are touching you.