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→Sound patterns: I wrote four more paragraphs based on the same source and gave a footnote telling this for each paragraph.
“Reflection” is when sound waves bounce off a flat surface. “Plane reflection” is when the sound bounces off a flat surface at an angle equivalent to the angle it came at the surface, like a ball bouncing off the side of a pool table. “Parabolic reflection” is when the sound bounces off a curved surface and disburses like the beam of light from a flashlight. “Elliptical reflection” is when the sound bounces off a curved surface and focuses on a point at some distance from the origin of the sound. For example, if one whispers on one side of the room, the sound is focused by the elliptical surface and the whisper can be hear at a point on the other side of the room.<ref name="Stevens & Warshofsky Chapter One" />
“Reflection” is when sound waves bounce off a flat surface. “Plane reflection” is when the sound bounces off a flat surface at an angle equivalent to the angle it came at the surface, like a ball bouncing off the side of a pool table. “Parabolic reflection” is when the sound bounces off a curved surface and disburses like the beam of light from a flashlight. “Elliptical reflection” is when the sound bounces off a curved surface and focuses on a point at some distance from the origin of the sound. For example, if one whispers on one side of the room, the sound is focused by the elliptical surface and the whisper can be hear at a point on the other side of the room.<ref name="Stevens & Warshofsky Chapter One" />
“Refraction” of sound is when sound waves change direction because of a change in what they are traveling through.<ref name="Stevens & Warshofsky Chapter One" />
For example, when the air is 32 degrees F, the sound travels at only 740 mph. At 68 degrees F, it travels at 767 mph: 27 mph faster. Because of this, when sound goes from a cool area into a warm area, the sound waves change direction. The day the cannons were fired in London because Queen Victoria died the sound refracted so much it reflected off the sky. The cannons were heard 90 miles from London although they were not heard only 40 miles from London.<ref name="Stevens & Warshofsky Chapter One" />
When the sound wave enters the warm layer of air at an angle, one end of the wave speeds up first. This somehow causes the angle (of the wave in relation to the line between cool and warmer air) to become less. “Simple refraction” is when the wave direction change is less than to critical angle. “Critical angle” is when the wave ends up traveling parallel to the line between cool and warmer air.<ref name="Stevens & Warshofsky Chapter One" />
A larger refraction causes a reflection. When the warm air is a lot warmer than the cooler air, the sound bounces off of the warm air heads back toward the ground – still moving away from the source of the sound. When a man yells on a winter morning on one side of a lake, the sound waves might bounce off the sky and be heard on the other side of the lake, but not in the afternoon when the ground is warmer.<ref name="Stevens & Warshofsky Chapter One" />
== Subcategories of Sound ==
== Subcategories of Sound ==
==References==
==References==