For a number of weeks now, Chris and Spencer's 3rd and 4th grade classes have been focusing deeply on sound, and I have been sharing activities with the students that allow them to experience sound vibrations in many contexts, and to understand that sound is transmitted through many mediums, including solid, liquid, and gas. I've also been helping the students to understand sound as wave, and how the frequency of sound waves effect the pitch and volume. We've used sound vibrations to carry messages, make rice dance, create patterns in sand, and to turn household objects into speakers. We've visualized sound waves using a "sound machine" that we built out of skewers and gumdrops (a favorite holiday project), and by mimicking the movement of air molecules using a slinky. In the slinky demonstration, we showed how the motion of molecules that are being vibrated creates a wave, and how the shape of that wave can be altered by increasing the speed or intensity of the vibration (moving the slinky more quickly or with greater force). Many of these activities have the added benefit of being a lot of fun! Soon we will be creating some instruments as part of a collaboration with Josh in music class.