A Boy and His Seismograph

Shane Shepherd's Home Built Seismograph

I thought that I could build a
working seismograph . I just
needed a Team Labs Rotary
Motion Probe, a spring, a
weight, some string and a
stand. Using these materials I
could build a seismograph
that could measure seismic
waves fairly well. I also
thought that I could locate a
ball in a gym by measuring its
seismic activity. If the waves
lessened, that meant that the
ball was farther away and if
they got stronger it meant it
was closer.



I needed a strong base for my
seismograph so I decided to use
a sturdy microphone stand. Then
I needed a weight so I used the
weight set that comes with the
Rotary Motion Probe. I used two
weights. Each weight weighed
.31 kilograms and the rod they
were attached to weighed .01
kilograms. I then attached a
string to the rod with the weights
on it and a spring. The spring
was mounted on a horizontal bar
at the top.

I used the Rotary Motion Probe
hooked to my computer to
measure the seismograph's
movement. The way the RMP
works is that it measures when a
wheel turns one fourth of a
degree or 1440 counts if it turns a
complete circle. I used a rod
with the circumference of 20mm
hooked to the wheel. Each time
it moved one count the ground
had moved .014mm (20 / 1440).
Each time the seismograph
moved a certain amount, my
computer would print out a graph
showing the movements.

Since there are
few earthquakes in Colorado, I
decided to try it out on floors. I
wanted to see if I could tell how
much a floor was moving when
people walked, jumped or
bounced a ball on it. I also
wanted to see if I could locate
where a ball was bouncing on a
gym floor by measuring its
seismic waves.

Try it out:
in the Kitchen
at the Mall
in the Warehouse
in the Gym

Shane's conclusion