A noisy day -Sound experiments

Trinity has been learning about how her guitar makes different sounds for the entire school year.  Her instructor went into detail about how the shape of the guitar, type of wood, size of the strings and positions she played all had an impact on the sounds it made.  He was also good with encouraging Trinity to use her guitar as a percussion instrument as well as a string.

Yesterday Trinity and Kyler enjoyed another day of experimenting, this time with sound. The pictures and her findings are as follows:

 

Sound travels in waves like if you snapped a belt it would make a shock wave the shock wave would bounce off the walls.

  We just did an experiment with a ruler and a string. Tie the string to the end of the ruler with a hole.  After you tied the string to it whirl above your head fast.  If it doesn’t work tilt it a bit. Doesn’t it sound like a light saber or a helicopter?

                                                Why does it make that sound?

Well, it makes that sound because when the ruler goes around it makes the air vibrate.   The faster the ruler goes the more the sound gets higher pitched.

All you do her is tie the string to the spoon and tie the other end to your finger.  Then you bang it on a leg of a table or on a chair. Then the weirdest thing about this experiment is that after you listen to the vibration the spoon makes when it hits the chair or table is you put a finger that you tied the string on to in your ear.

                                                Why does it make that sound?

It’s making that sound because the sound wave is traveling up the string into your ear.

                                

When sound travels through solid things the sound waves don’t spread out.  When sound travels through air the sound waves spread out so that the sound is heard more softly.

What you do on this experiment

Cut the balloon to the very top and put it on the cup so that it is covering the whole thing. Then put the elastic band around it. After that put ten or twenty grains of salt or sugar on the balloon and yell or scream right next to it. Don’t you see them dancing?  The louder you yell the more the sugar dances.  The sound waves make the balloon bounce like your eardrum.