Sounds All About Us - Exploring Science (1954)

e [Music] it was just before supper and David was watching television he was watching a motion picture and it was a noisy one a little too noisy David thought now he didn't mean to turn the sound all the way off but how different how different the picture seemed now how strange without sound sound is such an important part of our Lives yet David had never really noticed it before but now he began to notice sound he thought of other sounds we hear almost every day [Music] yes thought David sound is everywhere but what is it what causes it he remembered something he once did with a tuning fork then while it was making a sound he dipped into Waters the water splashed and the tuning fork stopped making its sound what did that mean he dipped it again but nothing happened when the tuning fork was silent no water splashed so when the fork was making a sound it must be moving to splash the water when the tuning fork was struck it started moving David couldn't see the movements but he could feel the movements with his fingers there was sound and there was movement so David understood something sounds we hear are caused by rapid movement of things we call these movements vibrations every time we hear a sound it means that something is [Music] vibrating sounds are caused by vibration watch see the guitar string vibrating sound and vibration your voice is sound but what is [Music] vibrating inside your throat your vocal cords are vibrating most of the time we can't see the vibrations that are causing us to hear sounds what sound is that David could tell by the sound that the airplane was flying away then there was another sound even without looking David could tell what it was the sound of an automobile different things sound different then David heard another sound it was Alice who lived across the street taking her singing lesson Alice's voice was different from the other sounds David had heard but the sounds that Alice was making were different from each other too how are the sounds different from each [Music] other some of the sounds are lower than others [Music] some of the sounds are higher than others High sounds and low sounds we say these sounds are different in Pitch we can hear differences in pitch in many sounds [Music] [Music] difference in Pitch is one thing that makes sound seem different what else makes them seem different [Music] listen some sounds are louder than others some are softer than others we say that this is a difference in loudness we can hear differences in loudness listen many sounds difference in loudness is another thing that makes sounds seem different to [Music] it and there is one more thing why does a note on the piano sound different from the same note that Alice [Music] things without even seeing Alice or the piano you can tell just by listening whether Alice or the piano is making the sound the sounds are different because different things are making them we say they are different in quality most sounds differ in quality we can often guess what is making a sound because we can recognize the quality of the sound [Music] quality is the third thing that makes one sound different from another thinking about Alice taking her scene lesson helps David understand many things about sounds sounds are caused by vibrations or movements of different objects sounds can be different in [Music] pitch sounds can be different in [Music] loudness sounds can be different in [Music] quality yes David understood sound much better now that he had begun thinking about it sound is everywhere and it's a very important part of our Lives David was sure he wanted to learn even more about s s [Music]