Changes

“Beat” is when two slightly different frequencies of sound waves combine to cause a sound with rising and falling loudness. This is because when waves are in the same place they join and become a bigger wave and when they are between each other they cause a flat “surface.”<ref name="Stevens & Warshofsky Chapter One" />  

“Beat” is when two slightly different frequencies of sound waves combine to cause a sound with rising and falling loudness. This is because when waves are in the same place they join and become a bigger wave and when they are between each other they cause a flat “surface.”<ref name="Stevens & Warshofsky Chapter One" />  

===Reflection===

===Reflection===

“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 disperses 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 heard at a point on the other side of the room.<ref name="Stevens & Warshofsky Chapter One" />

 

===Refraction===

===Refraction===

“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" />  

“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" />