Changing just the amplitude of a wave has several effects on the wave's characteristics:
Wave Height or Intensity: The amplitude directly affects the "height" of the wave. Increasing the amplitude makes the wave taller or more intense, while decreasing the amplitude makes the wave shorter or less intense. For example, in a sound wave, higher amplitude corresponds to a louder sound, and lower amplitude corresponds to a softer sound.
Energy of the Wave: The energy carried by the wave is proportional to the square of the amplitude. Doubling the amplitude increases the energy four times, while halving the amplitude reduces the energy to one-fourth.
Loudness or Brightness: In the context of sound or light waves, respectively, increasing the amplitude leads to a perception of higher loudness in sound and greater brightness in light.
Compression and Rarefaction: In longitudinal waves like sound waves, higher amplitudes lead to stronger compressions (regions of higher pressure) and rarefactions (regions of lower pressure).
Increased Maximum Displacement: In transverse waves (e.g., waves on a rope), increasing the amplitude results in larger maximum displacements of the particles from their equilibrium position.
Frequency and Wavelength Unchanged: The frequency (number of cycles per second) and wavelength (distance between two consecutive peaks or troughs) of the wave remain unaffected by changes in amplitude.
Waveform Shape: Changing the amplitude does not alter the basic shape of the waveform; it only affects the size of the oscillations.
It's important to note that changing the amplitude of a wave does not change its fundamental nature or speed. For example, sound waves will still travel at the same speed in a given medium, regardless of their amplitudes.