In April, we had fun learning about the physics of music at the DLC. I’ve put together some suggestions for those who would like to learn more about sound and music. I’ve tried to group them by topic, but please pick what looks interesting to you.
My favorite activity is to become aware of the sounds in our environment. I like to perform 4’33’’ by John Cage. You can learn more about it at http://en.wikipedia.org/wiki/4%E2%80%B233%E2%80%B3 In this piece no sounds are intentionally produced. Try performing it in different places (inside and out) to become aware of different sounds in the environment. Depending on your kids you may have to shorten the length. Afterwards, classify the sounds as natural or man made, discuss where the energy to make the sounds comes from and what vibrates to make the sounds. It is also interesting to listen for words which express sounds and keep a list. Sound-level meters ( $30-40 and Amazon, Radio Shack) can be used to measure and compare the intensity of different sounds. The data can be organized, graphed or used to study noise pollution and hearing safety.
Sound Waves
I demonstrated the Make A Wave Mobile in the percussion session. It is easy to make and lots of fun to hang in your house and play with. It demonstrates mechanical waves. It is available as a kit from RAFT or you can make your own. The directions are here http://www.raftbayarea.org/readpdf?isid=587 Another easy hands on activity from RAFT is the Wave Making Activity http://www.raftbayarea.org/readpdf?isid=210
We used an oscilloscope in class to examine sound waves. There are several free or low cost software oscilloscope programs online. I have not used them personally, but they may be worth exploring. http://xoscope.sourceforge.net/ for Linux is one. You can also examine sounds by using a computer recording program (Audacity http://audacity.sourceforge.net/ is free). Discover that the pitch of the sound depends on the number of vibrations in a given time (frequency) and that louder sounds make wider patterns (amplitudes). The best way to see this on Audacity is to record the sound and then pick a section of it to enlarge and look at closely.
For those of you into engineering, do an internet search on Tacoma Narrows Bridge, Washington State, November 1940. A wind storm caused some excessive vibrations.
Sound Quality
Listen to various instruments and discuss their sound quality. What is your favorite and why? Each instrument has overtones or extra frequencies which give a sound its particular quality. Use a computer recording program or oscilloscope to experiment. The sound wave for each instrument or each human voice will look different.
Sounds Can Travel Through Solids, Liquids And Gases but not a Vacuum
I highly recommend a trip to the Exploratorium in San Francisco http://www.exploratorium.edu/ They have an excellent area to explore sound including an exhibit that shows that sound cannot travel through a vacuum. If you decide to go, look at the exhibits online first to get ideas. There is so much to do it is overwhelming.
These other experiments can easily be done at home. RAFT Sound String Idea Sheet (cup and string telephone) http://www.raftbayarea.org/readpdf?isid=475 Secret Bells http://www.exploratorium.edu/science_explorer/secret_bells.html is a very good experiment that shows how sound waves travel into your ear. The experiment called head harp (discussed in the What’s Going On Section) can be found at http://www.exo.net/~pauld/activities/sound/headharp.htm It demonstrates sound vibrating through your bones into your ear. For older kids the Exploratorium has the following online exhibit about the perception of sound http://www.exploratorium.edu/exhibits/highest_note/
Swimming Pool Experiments are also lots of fun. Attempt to talk to each other underwater and use various devices underwater to make sound (ring bells, tap spoons together, tap on a pan, etc. )
Some Other Areas To Explore Might Be
Echos (reflected sound waves) This could include studying bats or other animals that use echolocation, ultrasound , sonar and how architects take sound waves into consideration when designing buildings and concert halls.
How Fast Does Sound Travel? Compare it to the speed of light. Learn about thunder and lightning.
RAFT Idea Sheets:
2-Tuba Phones http://www.raftbayarea.org/readpdf?isid=521 Make a trombone-like instrument with a slide
Buzz Off http://www.raftbayarea.org/readpdf?isid=19 Makes a noisemaker that shows the effects of air passing over a taut rubber band.
Glove-a-phone http://www.raftbayarea.org/readpdf?isid=82 We made this in the first class. If you missed it, it is worth doing. Be sure to experiment with tubes of different length and width.
Experiment Further With The Instruments We Made In The Classes
Try adding a finger hole to the glove-a-phone
Make a larger drum. Use a larger container and a larger balloon. I found some 36” balloons at a party store. A punch balloon would also work.
Experiment with different sizes and thicknesses of rubber bands on your string instrument. Palace Office Supply has very large bands that are used to hold artists books closed. They are fun to experiment with. Try setting the instrument on top of a box or other container to see if you can find a way to make it resonate. Try adding to your instrument or redesigning it to see if you can get it to resonate. (make more sound)
TOPS Science Tops has the following reasonably priced unit available http://topscience.org/ooks/sound18.html It is listed for grades 7-12, but parts can be adapted for younger kids. A class based on it may be offered at the DLC soon!
Posted by Charlotte 5/6/12
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