It takes many kinds of wood to make a guitar, and guitar makers have to be mindful about using wood that is in danger of being over-forested. Woods presented for visitors to handle, thump, and examine. The interactive is laid out as a series of woods arranged like a marimba (using maple, rosewood, mahogany, spruce, and plywood). Visitors can strike each with mallets and hear the difference in tone and volume that each wood produces. The interactive also highlights the concerns over disappearing forests.
Strings are made of catgut, nylon, and steel. Each has its own unique properties. Three guitars are strung with each type of string in a "guitar pyramid." Visitors strum each guitar and hear-and feel-the difference in each of the materials used to construct the string.
The guitar is a marvel of bent wood, carving, and glue... but no nails. This delicate thin wood box must be able to withstand 200 pounds of string tensions. Two acoustic guitars have been cut open to reveal the "inside workings" of the instrument. Braces are revealed, as are the dimensions of the wood (very thin) and the joints used to keep the pieces together.
The shorter the string, the higher the frequency. Visitors can test this by shortening cable and listening to the change in pitch. Bungee cords are strung across a sound table and tuned to different pitches. Each one can be depressed to form a note, but the real learning comes from how important surfaces are to producing sound. A string that is plucked in the air generates almost no sound, while pressing it against the sound table makes it very loud.
A barrel strobe allows visitors to see the vibrations of a string as if it was being played in slow-motion. Different strings vibrate at different frequencies, showing unusual patterns against a guitar backdrop. An oversized guitar with four foot-long strings sits over a barrel strobe, which-when spun-captures the waveforms of each string in a truly unique visual presentation.
The tuning pegs of guitars rely on gears to hold strings in place. A table outfitted with large plastic gears in sequence shows visitors how gears work. Users can spin gears of different sizes and will learn that gears next to each other always turn in opposite directions, and that different size gears are used to simplify mechanical tasks.
An electric guitar appears to be a simple device, yet it is made up of electronic components, magnets, different kinds of wood, bits of metal, and plastic. Looking underneath the sleek finish, there's more to the guitar than meets the eye. Visitors can flip switches, turn knobs, and see inside this Plexiglas instrument.
Visitors generate electromagnetic energy by spinning a wheel with evenly spaced metal pegs under a magnetic pickup. Only when the metal pegs pass by the pickup is a signal generated. The signal generates a sound at a specific pitch. The faster the wheel is spun, the higher the frequency, and thus the higher the pitch.
Using remote sensors, visitors can activate different sounds from different types of stringed instruments by waving their hands over lit panels. Each instrument shows how the combinations of wood, metal, nylon, and electricity are used to create different sounding instruments (from a ukulele to an electric guitar). The sensors are tuned so that users can hear the difference in tonality and can also create musical patterns.
The largest guitar amplifiers used by bands on a concert stage are over 6 feet tall. Visitors see into two different amplifiers constructed of Plexiglas. Speakers, tubes, electronic components, and structural elements are all revealed inside these musical monsters, showing how a guitar can be heard all the way to the back of a football stadium.
Decibel levels range from 0 to 194, and visitors can use a touchscreen to find out where everyday sounds fall on the decibel scale. This interactive also warns of the danger of constant exposure to loud noise. A touch-screen mounted inside an amplifier cabinet features 20 different sounds that are activated by the visitor. From a mosquito to a volcano, each sound is registered on a decibel meter that shows just how loud the world around us really is.
Listening to guitar riffs that bounce visually on a touch-screen, visitors are encouraged to test their memory in "remembering the riff." Musicians learn dozens, even hundreds of riffs over their lifetimes, and memory is important to performing and technical ability. This self-directed interactive proceeds from simple riffs to increasingly complex patterns using color as a reinforcement to each activated pitch.
Visitors get to choose the colors, patterns, shapes, and even textures in designing their own guitar using this touch-screen interactive.
This entertaining three-minute video, created by Dr. Mark Lewney, shows viewers how sound waves are generated by a guitar and how those waves change when they pass through an amplifier.