HereÃÂs a great ÃÂhands onÃÂ learning activity that lets kids make something, make a lot of noise, learn some math, and have something to take home with them.
Have your kids make a pipe organ, you buy the hardware.
The pipe organ could be a large cathedral type organ which would might cost a million dollars.
If that is to expensive, fifty drinking straws can be purchased for fifty-nine cents, and the math and the physics is the same whether the pipes are made of brass, gold, plastic, or paper. And each straw can yield several pipes, so a packed classroom of kids can be supplied rather cheaply, if you donÃÂt want to go the cathedral route.
Placing a finger on one end of the straw and blowing across the top of the other end creates a standing wave in the pipe and quick as a whistle, youÃÂre making music.
Cutting a second straw to make a shorter pipe and repeating the steps above, you have a new pipe and new note.
The easiest way to create your organ is to duplicate the sounds of a piano or organ that is known to be already in tune.
This can be done by trial and error, cutting as many straws as necessary.
Alternately, a non-destructive method can be used:
The straw can filled with water and held vertically with a finger pressed against the bottom to hold the water in. Then let some water leak out and blow across the top, and repeat these steps, repeatedly. Each time you blow across the top of the straw, you will hear a new note, if you have released some water each time ( increasing the length of the straw that is ÃÂfilled with airÃÂ ).
Add and release water until you have the desired sound, then cut the straw at the air / water boundary, keeping the top part as your properly tuned pipe.
If you donÃÂt have a piano in your classroom but you do have a computer and an Internet connection you can dial up a piano on your computer by going to the web page:
This allows you to play a piano on your computer so as you create each pipe, each will be properly tuned, otherwise your music will end up sounding sour.
First create pipes for the white keys on the piano.
Plan on making a lot of them.
Have the students measure the length of each pipe and plot the length of the pipe on graph paper. The quickest and most elegant way to create a graph is to lay the pipes together so they are all parallel and touching and aligned along the bottom, and bingo, you have a graph. ( Math doesnÃÂt have to be hard. )
Hopefully, the physics on your planet is the same as it is on mine, and perhaps a student will discover a relationship regarding the lengths of the pipes, whose lengths were determined by a tone matching procedure.
Then refer back to the ÃÂPiano / OscilloscopeÃÂ web page and play the note that corresponds to each pipe you have and record the frequency of each of note ( which the program conveniently provides for you ).
Use your own ingenuity to have the kids play a tune for you, each playing a single pipe.
This should be a fun and educational experience.
I hope you try it and fun with it.
If youÃÂre brave enough to try it, let me know how it goes.
-- Paul Flavin
Developer of Java programs. Writer of web pages. Cutter of straws and creator of things that make noise.
ÃÂImaging the Imagined : Modeling with Math and a keyboardÃÂ