Toys That Teach Technology

Sound and Vibration, Jan 2007 by Lally, Robert W

For many years, Sound and Vibration has presented an ongoing dialog between educators and consultants that seems to conclude that technical education ought to include both analytical and experimental learning tasks. Moreover, feature articles in S&V devoted to testing the behavior and monitoring the health of machinery and structures often include elaborate models of physical, graphical, mathematical and verbal forms. Inevitably, some of the dramatic events and puzzling oddities encountered in testing the behavior and monitoring the health of things have found their way into valuable educational structural models, called Technology Explorers, and into an executive toy version, appropriately called the Enigma(TM).

What are Technology Explorers? Technology Explorers (US Patents #6,962,260, #6,443,735 and pending) are desktop structural models instrumented with visual sensors resembling flexible lollipops. Structured mainly from sports items, such as hockey pucks and fishing line, they function to transfer forces of nature and man into motion and changes in motion into flexing of the sensors. Puzzling antics of the structures and sensors entertain, enlighten and educate. A new word 'eneract' was coined to contract the formidable term, energetic interaction, which is how things naturally interact through transfer of energy. The Enigma, an executive toy, contains all of the Technology Explorer ideas integrated into a simple, elegant, unified design; it is pictured in Figure 1.

Behavior testing involves disturbing a structure and observing (or sensing) the motion, similar to the way a doctor tests your reflexes. Afterwards, the doctor might tell you that when forced or pressured to do something, you feel the stress and the strain shows. The same thing can be said about a test object. Like humans, inertial motion sensors employed in Technology Explorers flex to structurally sense changes in motion caused by interacting objects transferring energy by pushing and pulling on one another, on the earth and on the sensors.

Dynamically flexing 'lollipops' are easy to see when the structure is perturbed. Since you do not have the Enigma sitting in front of you, I will utilize a different type of sensor to record graphic images for your consideration. Figure 2 illustrates an Integrated Circuit Piezoelectric Inertial Motion (ICPIM) sensor available as an adjunct to the Enigma. This two-wire accelerometer provides an analog voltage proportional to acceleration. An inexpensive DAQ card fitted to a laptop computer permits recording and viewing dynamic signals from Enigma experiments. Typical results are shown in Figures 3-5.

Baffling Behavior. Testing the behavior of the Enigma, experimenters encounter puzzling mysteries. Remembering the soothing, relaxed feeling you enjoyed when coasting on a simple childhood swing may help you to resolve some of the mysteries.

When coasting sideways as a glider-type swing, the lollipop sensors normally flex to sense motion, as expected. Surprisingly though, when coasting fore-and-aft as a simple swing, tangential motion sensors do not flex or sense the swinging motion, but the radial motion sensors flex to indicate motion when there is none (see sidebar).

When side weights are centrally added, the swing continues to coast and accelerate the same as before the change. The coasting motion does not change, in spite of the increased force and inertia. When elastically suspended with bungee-cord, the swing bounces while coasting. When lifted and dropped under certain conditions, the elastically suspended disk apparently does not bounce, but the side sensors fluctuate wildly. Solving these baffling behavior mysteries helps develop deeper insight into the dynamic nature and behavior of things, especially sensors.

Applying Technology. The structure of the Enigma embodies, demonstrates and helps teach the technology needed to solve the mysteries encountered, as well as many other of life's perplexing puzzles. In the Enigma, interacting mechanical objects transfer energy by pushing and pulling on one another. They move, flex and animate things, trigger and power events and communicate information. They behave in accordance with laws of nature, such as Newton's and Hooke's. Moving is opposed by inertia, stiffness, friction and gravity, which store or dissipate energy in different ways.

Connected inertial and elastic objects form systems that oscillate at natural rates in various patterns, as the direction of the force and energy transfer automatically reverse. Structures typically contain many such resonances, which can create beautiful music or noise pollution; they can please, annoy or destroy.

Electrical objects transfer energy by potentially pushing and pulling on one another to move electrons as electrical current, creating magnetic and electric force fields. Movement of electrons is opposed by resistance, capacitance and inductance. Electrical energy is stored in different ways, in accordance with the laws of nature such as Ohm's law and the law of electrostatics.