Cold air hovering over a lake traps and echoes sound across the water

Evidence

Sound waves travel at different speeds depending on the temperature, so the cold, thin air layer that hugs the surface of the lake puts an invisible ceiling on the lakeside amphitheater, enclosing the sound, with remarkable results. Sound echoes back and forth across the lake, connecting everyone and everything. — Gordon Hempton, John Grossmann, One Square Inch of Silence- One Man’s…, 241

Categorization

• DEFINE: Explains the physical mechanism by which a cold lake acts as a natural acoustic amphitheater.
• SEED: An essay angle: mapping natural acoustic phenomena (lakes that amplify sound, valleys that carry it) as a way to write about place through the ear rather than the eye.
• corroborated: 2 independent passages support this claim — Gordon Hempton, John Grossmann, One Square Inch of Silence- One Man’s…, 241
• XREF: connects to: Cold water layers create a natural acoustic amphitheater — Gordon Hempton, John Grossmann, One Square Inch of Silence- One Man’s…, 241; An echo is partly an original sound from the reflecting material — Gordon Hempton, John Grossmann, One Square Inch of Silence- One Man’s…, 927

Broader Connections

• An echo is partly an original sound from the reflecting material #expands (0.60) — Gordon Hempton, John Grossmann, One Square Inch of Silence- One Man’s…, 927