Sounds are vibrations that travel through the air or other mediums, creating waves that our ears can detect. These vibrations can come from various sources, such as musical instruments, voices, or natural phenomena like thunder and waves. When these waves reach our ears, they are converted into signals that our brain interprets as different sounds. The characteristics of sound include pitch, which determines how high or low a sound is, and loudness, which indicates the intensity of the sound. Sounds can be classified into categories like music, speech, and noise, each serving different purposes in communication and expression.