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Showing posts from February, 2012

PVC Steam Whistle

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materials: •1/2''-1'' pvc pipe •1/2''-1'' wood dowel tools: • fine toothed wood saw and a miter box or a scroll saw • a chisel and hammer The first step is to make a flat on the lower dowel plug.  You can do this either by cutting into the end of a long dowel with a saw (at about 1/3 the diameter) then cutting off the two slices about 1'' long,  or cutting off a section of dowel about 1'' long and slitting it with a chisel and hammer to create the flat. The next step is to cut out the mouth of the whistle, cutting a little less than half way into the diameter and then in at a 30 to 45 degree angle to remove the slice. Insert the dowel with the slice taken out of it into the lower side of the whistle so the flat faces the mouth of the whistle. The top of the dowel should be level with the bottom lip of the mouth for the best sound.   Note that pvc and dowels are not all that consistent in diameter so you might have to add so

Canjo

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Materials: •1/2'' dowel (about 2' long) • coffee can (we like the kind with steal bottoms and cardboard sides as its easier to put holes in them) • 50lb test fishing line • small eye screw • a finishing nail • a cork or a small piece of wood Tools:    • scissors • hammer  • a file or a small saw  To start the instrument carefully use a nail to mark the position for the dowel hole, making sure that its low enough that the dowel will not touch the surface of the can when inserted.  When you're satisfied with the positioning of the holes use a pair of scissors to widen them out so they are just smaller than your dowel.  In the past when we were making these with large groups we would pre-prepare the cans to this step, as there is tremendous learning potential in these steps and mistakes here can hinder the function of the instrument later. Sand the corners off of your dowel so it can be press fit into the can wall as seen ab

Sound Projects

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There are a lot of good sound projects out there, and in the past when we've explored sound with students we've started with a variety of wind instruments developed by other organizations.  Below I will list some some of our favorites, with some modifications and technical notes. Slinkys and waves: At the most basic conceptual level sound is about waves, but not like ocean waves that oscillate up a down but rather waves of compressed material traveling through space. Sound, to many kids surprise, can travel  through any type of matter, traveling faster in non-compressible materials like water and metals and slower compressible things like gasses and spongy solids. To complicate matters further sound will travel faster in light material than in more massive material. The best simple demonstration of this we found is The Exploratorium's Slinky in Hand   science snack, it gets at the difference between a transverse wave (a water wave b.) and a compression wave (a sound w