Get physical at a great “body-on” car show at Carnegie Science Center and discover how cars really work. Square Wheels doesn’t sell you on the latest expensive technology—like a computerized satellite positioning system on your dashboard to help you navigate to the restaurant or pick a highway without traffic congestion. It doesn’t thrill you with polished Vintage classics, arranged like antique furniture for inspection. Square Wheels isn’t 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. It’s 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, it’s 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” around—mechanics, fluid dynamics, thermodynamics, basic physics, optics, audio and mathematics—gives 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. Here’s 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 won’t 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 don’t 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 don’t 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
isn’t likely to solve your mechanical problem. It’s beyond your control.
|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 you’ll 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. “It’s an exciting prospect each time the science center offers things you can’t 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: “It’s 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 engine—the 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. That’s the way the explosive air/gas mixture compressed in an engine’s 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 bicycle’s 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 vehicle’s 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 it’s obviously really about the entire physical world. It’s 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 it’s 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 you’ve ever touched a hot muffler you know. It converts sound to heat energy.
At one point it’s even a show about the principle of chaos in life. Every system contains some “Chaos”—a 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 you’re 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 didn’t 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 level—giving you a smooth ride. It’s 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. It’s a perfect fit. If you could design a road appropriately, any regular polygon (except a triangle) could serve as the shape of a car’s 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