27 Pipes
by Soren Schlassa
26 imagine
Science Olympiad is a multidisciplinary competition in which teams of up to 15 students
compete against teams from other schools in more than 20 events at the regional, state, and
national levels. Events rotate each year, ensuring teams a fresh slate of science and applied
science challenges. Here, four-year Science Olympiad veteran Soren Schlassa shares his
experience in a particularly challenging event: Sounds of Music.
S
ounds of Music has, as my Science
Olympiad team’s head coach put it, a
reputation as “the mother of all building events.” Two students each build an
instrument from scratch, arrange and perform a
duet and an assigned piece, give a brief interview
on the construction of their instruments, and take
a test on the physics involved. I had never encountered a music-themed Science Olympiad event in
my previous three years of participating and was
intrigued by the challenge.
Four years of playing classical guitar had given
me a basic understanding of music theory. My partner, Katie Dillon, had a much more comprehensive
knowledge than I, which aided her in constructing
her instrument: a bass dulcimer. After coordinating
a timeline that would allow us to practice together
before the competition, we went our separate ways
to build our instruments.
I decided to build a xylophone, and I knew I
wanted to use metal. I soon realized that metal bars
require complex shaping to produce good tone
quality, so I decided to build a pipe metallophone.
My father and I tested copper and aluminum pipes
of varying diameters, lengths, and thicknesses we’d
bought from a local hardware store, as well as some
old copper pipes from the garage. After kneeling
in the kitchen for hours, striking various pipes,
checking their tuning, and noting their tone quality,
I decided to use the copper from the garage. Not
only did it have slightly better tone quality, but it
was free.
The rules allowed a range of just over three
octaves: 27 notes, from F3 to G5. The minimum
was one octave: C4 to C5. If my xylophone could
produce the full range of notes, we would earn extra
points, and I’d have more versatility in my performance. This meant that I needed 27 pipes, which
would eventually range in length from over half a
meter to less than 25 centimeters.
Shaping the Notes
Before I started building my xylophone, I had to
learn about the physics of tube idiophones (instruments that produce sound by the vibration of the
instrument itself, without the use of membranes or
strings): how to tune them, how to determine what
length the pipes should be, how to mount them to
bring out the desired notes’ fundamental frequency.
In my research, I found an equation used to estimate the length of a pipe, taking into account the
diameter and wall thickness of the pipe, the speed
of sound in the material, and the desired frequency.
After researching the speed of sound in copper
(3700 m/s) and measuring the diameter and wall
thickness of my pipes with a caliper, I used the
equation I’d found to estimate the length of pipe I
needed for each note. Actually cutting and tuning
the pipes turned out to be quite a process. I cut each
pipe with a handheld pipe cutter, the kind that you
tighten onto the pipe, turn, tighten more, turn, and
repeat until the pipe breaks. Then I checked the
pipe’s tuning with my guitar tuner. If the note was
flat, that meant the pipe was a little too long, so I
would take it to the garage to grind it down with my
grandfather’s bench grinder.
Although I wasn’t yet sure exactly how the
pipes would be mounted, or to what, my father
and I drilled holes in them just in case. In my
research, I had learned about the concept of nodes,
points along a wave where the amplitude is zero.
To emphasize a note’s fundamental frequency in a
pipe, I learned that I needed to mount the pipes at
nodes, which, for all pipes, are located at 22.4% of
the pipe’s length from each end. That is where we
drilled the mounting holes.
May/Jun 2012
thinkstock
Finishing Touches
Now I had to deal with the appearance. Points would be
awarded for workmanship, so my 27 oxidized, ugly pipes
had to be cleaned. Research and testing yielded citric acid
mixed with salt as the most effective way to clean them.
Over the course of a week or so, I scrubbed one pipe at a
time in the kitchen sink, then discovered to my dismay that
the pipes were oxidizing again. It turned out that I needed
to neutralize the acid and then apply a store-bought, painton coating to stop the pipes from oxidizing.
In one night, in a race against oxidation, my father and
I scrubbed the pipes with citric acid, neutralized them with
baking soda and water, scrubbed them with a foul-smelling
polish, and finally scrubbed them with isopropyl alcohol
to remove the polish. We then hung them up on a piece
of fishing line across the garage, using binder clips to keep
them from sliding together, and painted them with a coating to prevent oxidation. After two coats, the pipes were
ready to be mounted.
We stuck two lengths of adhesive-backed weather stripping, which struck a good balance between dampening
the notes and allowing them to ring, to the top shelf of a
rack we bought from Costco. Zip ties—white for naturals
and black for sharps—connected the pipes to the rack and
weather stripping through the holes at the nodes.
The final step of construction was to find mallets with
which to play the xylophone. After experimenting with
everything from wood to my fingernails, we found an
especially good option: screwdrivers whose handles had
a plastic core and rubber coating. These provided a loud
enough sound without too much harshness. Once we had
finalized the mallets, there was a moment when I turned
around, looked at my dad, and said, “Are we done?” After
some confused blinking and mumbling, we realized that we
were indeed done but also that it was very late and not at all
the correct time to begin learning to play the instrument.
The sense of accomplishment came the next morning,
when I couldn’t stop playing it.
I
n the week before the competition, Katie and I arranged
and learned two duets. One piece, St. Anthony’s Chorale,
was required. For the other, we combined In the Hall of the
Mountain King by Edvard Grieg and Tubular Bells by Mike
Oldfield into a piece we titled In the Hall of the Tubular Bells.
It wasn’t until the night before the competition that we got
both pieces down.
At the competition, Katie and I were the first of the 39
teams to perform for the judges. The performance went
well, and, after all we’d done and learned as we planned,
constructed, and played these instruments, the interview
and written test were a breeze. It was the awards ceremony
that heralded the excitement and satisfaction of a secondplace finish.
The xylophone is still in my living room, where my dad
or I will walk by and play a few notes most days, though
I’ve mostly lost my ability to play it compared to the official
performance. Making this xylophone was quite an experience, but I think next year I’ll choose a different event.
Soren Schlassa is a sophomore at
Pacific Ridge School in Carlsbad, CA,
where he participates in Model UN
and Science Olympiad. In his free
time he enjoys doing math homework,
playing frisbee, hiking, and
backpacking. He looks forward to
attending The School for Ethics and
Global Leadership in Washington, DC, this fall.
Learn more about Science Olympiad at http://soinc.org.
www.cty.jhu.edu/imagine
imagine 27