A wave transmits energy and is massless. It sometimes, but not always, requires a medium (sound waves do require a medium). Waves come in two varieties, longitudinal and transverse waves. The sound waves we will be playing are longitudinal waves. The reason pure waves are called sine waves is because a graph of the sine trigonometric function is usually used to model these waves.
Waves have various properties, including their amplitude, wavelength, frequency, and wave speed. Wave speed is the same (the speed of light) for all electromagnetic waves. Sound is not an electromagnetic wave, however, and travels much slower than the speed of light. A wave’s wavelength is the total distance it takes for one whole wave to complete. A wave’s amplitude is how far up and down the wave goes when traveling. A wave’s frequency is how many waves occur in one second, measured in cycles/second, or Hertz (Hz). It is the frequency of a wave which determines many different properties of a wave. For a sound wave, the frequency determines the pitch of the sound. High-pitched sounds have high frequencies, and vice versa. This is why the website adjusts the wave’s frequency, as this is what changes the actual “pitch” of the sound you hear.
Waves' frequencies determine many different properties of waves. For example, in electromagnetic waves, the higher the frequency, the higher the energy in a wave. For example, gamma rays are the highest frequency of electromagnetic waves, and these waves are in turn the most-energy filled and deadliest in the electromagnetic spectrum. For sound however, the higher the frequency, measured in Hertz, the higher pitched the sound will be. Humans have a hearing range of 65 to 20k Hertz, while Dogs have a hearing range of 67-45k Hertz. Some people have a disorder known as ultrasonic hearing, in which they can hear waves of higher frequencies, such as 37k Hertz. Sound waves are important, interesting, and are very vital to our knowledge of waves in Physics.