|
|
Previous Sculpture||
Next Sculpture
"Trajectory Demonstrator"
Children throw things all the time. Sometimes, they throw things that shouldn't be thrown for no reason at all. Rather than
become mad at their unruly behavior and isolate them in time-out. Realize that it's actually their inner physicist controlling their
behavior. The object flying through the air is not unruly behavior, it is an experiment in physics as they learn the basics of
trajectory motion and trace the parabolic path of your priceless family heirloom. Education before experimentation can prevent this
from happening. Simply bring your child to the Great Lakes Science Center and let them experiment all they want... in a controlled
environment... with bouncing golf balls. Presenting the "Trajectory Demonstrator"...
This rolling ball sculpture is actually an exhibit. It is part of the exploratorium section of exhibits where visitors get to learn
fundamental concepts of science through hands-on learning. I was approached with the task of developing an exhibit which introduces
the concepts of trajectory motion, while showing the strong links to mathematics.
 The concept of trajectory was introduced by looking
at the projectile motion of a bouncing golf ball. As the sculpture runs, balls fall from the top track and bounce onto a granite block.
The person interacting with the sculpture can tilt the block, using an external lever, and change the bounce angle of the ball. This
changes the ball's trajectory as they try to hit various targets down-range. To convey the connection to mathematics, graphics are
used to clearly show the angle of the lever and simple projectile motion equations are shown in the background. The graphics contain questions
about the motion of the ball and how it relates to the angle of the bouncing surface.
The Background graphics also contain images of items that exhibit projectile motion. I used photographs that I personally shot in the local area.
I used images of fireworks from Blacksburg, VA, a popular local waterfall called The Cascades, and an image of me welding in my shop. Rather than explain
how these images exhibit projectile motion, I simply present the image and ask if they can think of any more. That really gets them thinking.
Using golf balls presented some unique challenges, such as reducing the track noise when the ball is rolling. The problem is that as the dimples on the golf ball
hit the track surface, the vibrations are transmitted through the mounting point and into the back board. The backboard and the whole enclosure
would then become a sound box, amplifying the sound of the rolling golf balls. To fix the problem, I designed mounting points that utilize rubber dampers in order to
isolate the vibrations. I use this same damping method to lessen the impact of the balls when they hit a target. I now use this same damping method
in all of my sculptures where a ball is dropped or caught, or where I need to isolate sound.
The sculpture has 8 targets that you can hit as you sweep through the angles. When you don't have the angle spot-on, the golf ball will drop dead with a
thud and roll back to the lift at the bottom. What are the targets?
- Hit a ramp and send the ball scooting under everything, into a switch to sound a fire bell.
- Hit a 15" Crash.
- Fly over a double bongo ball hop.
- Catch the ball in a basket, where the ball rings three small bells.
- Ring a loud cast-iron bell.
- Bounce off a bongo and into a basket, where the ball is funneled onto a track. The track sends the ball through chimes, off a drop and through step-downs.
- Bounce off a marble slab and into a Cowbell. (Cause everything could use more cowbell!)
- Bounce off a marble slab and into a Gong.
Since the sculpture is always running, I wanted the balls to have a predicted path, rather than flying to whatever
target was last hit. Therefore, When nobody is playing with the sculpture, the lever and granite block automatically return
to a "normal state." In the normal state, the balls continually drop off the top track, bounce off the granite block,
and fly into a basket. From there, the balls roll down a length of track, cross a break in the track by bouncing off a marble block, roll through
a wobbly spiral and return back to the collection point. Many people are happy just standing and watching this series of events. Then, they realize
that they can change the bounce of the ball and play with it...cracking a smile, they approach the lever. Now they are really going to have fun!
Next time you visit Cleveland, visit the science center and play with the sculpture! Click on the map for location information and directions
by Mapquest.
Previous Sculpture||
Next Sculpture
|
|
