Get physical at a great body-on car show
at Carnegie Science Center and discover how cars really work. Square Wheels
doesnt sell you on the latest expensive technologylike a computerized
satellite positioning system on your dashboard to help you navigate to
the restaurant or pick a highway without traffic congestion. It doesnt
thrill you with polished Vintage classics, arranged like antique furniture
for inspection. Square Wheels isnt about the usual car stuff: money, advanced
engineering, luxury, speed, and automotive style.
No, Square Wheels is about the basics,
the fundamental science that allows your car to move, turn and stop. Its
all about basic science, and as Jennifer Neuman of Carnegie Science Center
says, Some of the most exciting science is basic science.
More than a hands-on show, its a body-on
show that kids and adults will have fun with, as they literally grasp and
manipulate the technology behind automobiles. You may be pushing cylinders,
bouncing on springs, spinning centrifugally, or hoisting yourself into
the air, but you are also experiencing basic science at work. What children
and adults are likely to detour aroundmechanics, fluid dynamics, thermodynamics,
basic physics, optics, audio and mathematicsgives them a thrill here.
Automotive engineering and the internal
combustion engine have never before been so friendly, and the car has never
been so lovable, as they are in Square Wheels. Heres car show with a giant
engine where you can become a piston, and move large foam gears to see
how power is transmitted. Here is where oil and water mix to show you how
fluid dynamics work, and where you learn about geometry by peddling a Fred
Flintstone car smoothly along a crazy corrugated track.
The truth about modern cars is that they
run much better, much longer, and much more efficiently than they ever
used to. Knowing the scientific principles behind them wont turn you into
a mechanic. Getting out your checkbook may be as hands-on as you get when
it comes to repairs.
The trade-off for modern automotive performance
is that only a trained mechanic can really understand and fix most of the
technology built into the new cars. Gone is the old carburetor, the delight
of the tinkering generation. Now little computer chips run modern fuel
injection systems, gathering information from sensors that feed data about
temperature, barometric pressure, engine speed, manifold vacuum, and other
stuff you dont want to know about. Gone are primitive suspension joints
at the wheels, replaced by more sophisticated and expensive constant velocity
joints.
When you open the hood of a modern front-wheel
drive car you face a package you dont really want to take apart. Everything
is loaded tightly over the front wheels to give them the added weight and
traction they need to pull the car forward. The rest of the car is usually
comparatively light, which is why you get that great gas mileage. But under
the hood, everything is part of a system, and attacking it with your screwdriver
isnt likely to solve your mechanical problem. Its beyond your control.
If the wheels are square and the track is bumpy,
why is this ride smooth? At Square Wheels, adults and kids
have fun doing many activities together.
But, if you understand the basics, at
least you will understand what your mechanic is saying to you, and why
cars have certain problems. You may not be happy about the cost of car
repair, but at least youll have some knowledge, and see why a $10 part
is now a component in a $300 system your car needs.
As a traveling show, Square Wheels was
designed to push the envelope of first-hand science learning experiences.
It was developed by designers, technicians and educators at the Center
of Science and Industry (COSI) in Columbus, Ohio. The CEO and president
of COSI, Roy L. Shafer, says the show creates new world standards that
challenge young minds to explore fundamental math and science concepts
in a totally new way. COSI deliberately picked the automobile as the most
popular and friendly vehicle for explaining basic science.
Teachers are going to love this show,
says exhibit developer Linda Ortenzo of Carnegie Science Center. Its
an exciting prospect each time the science center offers things you cant
do at home, or do in school-but that are ready and waiting here. She
saw Square Wheels at Franklin Institute in Philadelphia, and says that
this is guaranteed fun for everyone: Its an interactive, experiential
exhibit, of the kind
Get inside the GIANT
ENGINE, for starters. Here visitors become human spark plugs,
using their feet to push pistons down to turn the crankshaft. The crankshaft
transfers its power to the transmission, which turns the wheels to make
the car move. Forget all those invisible parts inside the enginethe crankshaft,
sparkplugs, pistons, timing chain, timing belt, connecting rods, camshafts,
and valves. Engines produce power, and here you understand you get power
by pushing your feet.
The AIR CANNON
lets you find out more about where the power in a real car comes from.
With this cannon you propel a tennis ball into the air by dropping a bowling
ball. The air compression and pressure in the air cannon transfers the
momentum and kinetic energy of the dropping bowling ball to the tennis
ball, and shoots the tennis ball out of the cannon into a net. Thats the
way the explosive air/gas mixture compressed in an engines cylinder transfers
its energy to a piston, and moves it rapidly down, turning the crankshaft.
What else in a car uses compressed gas
or fluids? How about the brakes, which are moved by compressed gas or fluids
in the brake lines to stop the car.
Try the GEAR DOWN
experiment to appreciate the power of gears. With the help of up to ten
other people, try to stop from moving the largest wheel in an incredible
1000 to 1 gear ratio. You lose. One person turning the small gear has
more power than ten people trying to stop the turning of a larger gear.
This demonstrates the mechanical advantage of gear ratios, and the trade-off
you make between choosing either power or speed in automotive gear systems.
You can ask yourself further question. Do a bicycles gears work the same
way?
Speaking of power, how can one lift the
engine out of a car, and even lift a car itself? You find out in PULLEYS
and JACK STATION. With Pulleys you
hoist yourself into the air and find out the advantage of using more pulleys
to lift more weight. In Jack Station you see the difference between a screw
jack and a hydraulic jack in and supporting a vehicles weight.
And once a heavy car is moving in a straight
line, why do you have to slow it down before turning a corner? A powerful
gyroscope inside the FLYING BRIEFCASE
makes the point. When you walk in a straight line carrying this briefcase
everything is normal. But when you turn a corner, the briefcase resists.
The angular momentum of the gyroscope inside the briefcase resists the
attempt to change its orientation. Think about other things that remain
stable when spinning like tops and Frisbees.
On the surface this show may be about cars,
but its obviously really about the entire physical world. Its about light
waves, for example. How do high and low beam headlights work? In LIGHTS
ON you adjust and manipulate the focal length of automotive
lamps and reflectors. The distance between the bulb and the reflector influences
the angle and intensity of the light beam. Or its about sound waves. In
QUIET
ZONE you listen to the difference between the sound of a car
engine that has been filtered by a muffler and the sound of an engine that
has not been muffled. A muffler results in a sound depletion of up to
98% of the noise produced by an engine. How does a muffler absorb and diffuse
sound? If youve ever touched a hot muffler you know. It converts sound
to heat energy.
At one point its even a show about the
principle of chaos in life. Every system contains some Chaosa difficult
concept to understand. When you drive a car, for example, you have to leave
room for the unexpected, some space for disorder and confusion. Think of
how a line of fast-moving cars reacts when the first car suddenly puts
on its brakes. Every other car reacts immediately and individually. Disorder
and confusion is transferred throughout the whole line. If youre not prepared
for this as a driver, you become one of the pieces in a chain-reaction
crack-up. Chaos theory is a pretty advanced topic to pursue at a car show.
At CHAOS, you adjust the frequency
of a moving piston to cause a ball to bounce chaotically on it. Can you
make the ball bounce the same height every time? Why not?
The longest lines at this show are always
at SQUARE WHEELS. This experimental
buggy gives you a moment of profound scientific discovery. Square wheels!
I didnt know they could do that, said 12-year-old Christie Prince of
Brooklyn, N.Y., when she pedaled the experimental car across the jagged
concrete road. She and her schoolmates were trying it out at the Boston
Museum of Science. You could use this for the potholes, said one of her
friends. Pittsburghers would agree.
As the rubber-coated square wheels drop
into the spaces between the arches of the road, the axle of the wheels
remains levelgiving you a smooth ride. Its all about geometry. The length
of the sides of the square wheels is the same as the length of the sides
of the arches in the road. Its a perfect fit. If you could design a road
appropriately, any regular polygon (except a triangle) could serve as the
shape of a cars wheels. But for millions of automobiles, a circular tire
on a flat road surface makes the most practical combination for ease of
travel. Considering that wheels of just about any shape are physically
possible, ask yourself why round wheels are best for the cars we drive.
Beneath all cars beats the heart of basic
science. Cars really are all about physics and geometry and thermal dynamics.
When you get on the pogo stick at Square Wheels, you bounce straight into
the heart of the shock absorber, and on the way learn about suspension
systems.
-R. Jay Gangewere
