Concept:

The idea was to visualize the relation between data taken from a light sensor and translating this into a sonic pulse to be heard audibly. As a metaphor I chose to visualize the visible light spectrum and how we think that as a colour range as opposed to being comprised of individual entities. Association of these colours are often made to emotions and in a similar way I chose to visualize this by assigning separate intensities of light to the different sounds produced by my buzzer. As the intensity of light grows so too does both the amplitude and pitch of the sound waves, mirroring the way light waves compress and increase intensity as the spectrum goes on.

Sensor:
Light Sensor
 
Displaying data:
The data will be expressed through the pitch and volume of the sounds projected by the pulsing buzzer. A wide range of sounds can be produced by manipulating the light input in different ways creating tunes. This could even be expanded on to create light sensitive instruments in future projects, though likely that would require the use of heat or other non-touch sensors. 
 
Changes from proposal:

Originally I planned to visualize audiowaves as waveforms but due to my bumbling around with Electret microphones for a week before realizing i needed a pre-amp and it still having not arrived I'm more than happy to have changed my concept.

Code: 

//The code is pretty simple and based on one of the Arduino examples but it ended up working so why artificially complicate it.
// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}
// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // print out the value you read:
  Serial.println(sensorValue);
  delay(1);        
}