A small carpeted room with uneven diffusers covering the walls
A dense grove of trees surrounded by open sky
A hall of brick and plaster with soft wooden floors
A massive empty stone structure with high ceilings
A wide open grassy field
A fiberglass storage cylinder filled with water
A narrow brick archway at the park
A hardwood court with smooth concrete and glass walls
Whoa! Look at that explosion of color dots.
Sounds don’t really explode like confetti. They are mechanical waves, triggering a chain reaction of vibrating particles before they reach your ears.
Did you just see a burst of red or orange dots?
They represent low-pitched sounds with low frequencies. They’re difficult to absorb and more likely to travel longer distances.
Did you just see a burst of blue or purple dots?
They represent high-pitched sounds with high frequencies. They’re more likely to disperse or decay as a result of small changes in environmental surfaces.
Did you notice dark borders around that environment?
They represent soft, fibrous materials that convert sound into heat energy. In those places, we hear silence.
Did you notice bright lines around that environment?
They represent hard, smooth materials like stone or subway tile: sound bounces right off. In those places, we hear echoes and reverb.
Did you notice wavy lines around that environment?
They represent bumpy surfaces that trap sound waves. In those places, reverb and echoes are muffled.
Did you notice smooth, straight lines?
They represent small amounts of surface diffusion. In those places, high-pitched noise might scatter but bass lines carry.
Did you hear an echo?
Hard, smooth surfaces cause sound waves to bounce back towards the sound source.
Did you hear a really long sound?
In small spaces, reflected sound waves reach our ears instantaneously. We hear a prolonged sound, or reverb.
Did you hear a sound go silent?
Particles in soft, fibrous materials vibrate then turn into heat energy when sound waves reach them.
Did you hear a sound get muffled?
The nooks and crannies of diffuse surfaces trap and mute sound waves.
Did you hear a sound fade away?
Particles in the air vibrate as sound waves travel. Eventually, this kinetic energy slows down and the sound stops.
How do our surroundings affect sound waves and shape what we hear?
ABOUT THIS EXPERIMENT
At any given moment, we are surrounded by human, mechanical and natural sound. Whatever the source, these auditory vibrations are always co-authored: from the ground to the sky, from city walls to a forest grove, the materials and objects in a place impact the structure and movement of sound as it travels to our ears. This National Science and Technology Medals Foundation interactive invites you to discover the ways that physical space affects sound waves. By listening to words, beats, and naturally-occurring sounds in distinctive environments, you will observe how the properties of reflectivity, absorption, and diffusion shape the quality of what we hear.
The NSTMF’s mission is to build inclusive STEM communities across the United States. Fundamental to these communities are the significant, inspirational connections we foster between the individuals who have received national recognition for excellence in STEM and today’s diverse generation of college and high school students. Together they will pave the way for a more equitable future in science and technology.
Learn more about the NSTMF’s inSTEM program!
Learn more about NMS and NMTI Laureates
