1. Reflection:
* Hard surfaces: When a sound wave hits a hard surface like a brick wall, a large portion of the wave energy is reflected back. This means the amplitude of the reflected wave is close to the amplitude of the original wave. This is why we hear echoes from hard surfaces.
* Soft surfaces: Soft surfaces like carpets or curtains absorb more of the sound wave's energy. This reduces the amplitude of the reflected wave, making the echo quieter or even non-existent.
2. Absorption:
* Porous materials: Some materials like foam or fabric are porous, meaning they have many small holes. These holes trap sound waves, converting the wave energy into heat. This reduces the amplitude of the sound wave as it passes through the material.
* Thick materials: Thick materials, even if not porous, can absorb more sound energy than thin materials due to the longer path the sound wave has to travel through.
3. Transmission:
* Thin materials: If the wall is thin enough, some of the sound wave will pass through it. The amplitude of the transmitted wave will be lower than the original wave, as some energy is lost to reflection and absorption.
In summary:
* Amplitude increases: The amplitude of the reflected wave can be similar to the original wave if the surface is hard and reflective.
* Amplitude decreases: The amplitude of the wave decreases if the surface is soft and absorbs the sound energy, or if the sound passes through a porous material.
* Amplitude remains the same: The amplitude of the wave doesn't change significantly if the sound wave is transmitted through a very thin material.
The exact change in amplitude depends on the specific properties of the wall material and the sound wave itself (frequency, intensity, etc.).
