Sound is a type of energy that travels through the air or other medium, such as water or solids, in the form of waves. The human ear and scientific instruments that measure sound waves can both detect these waves because vibrating objects like vocal cords, musical instruments, or machinery produce them.

Sound waves are characterised by their frequency, which determines the pitch of the sound, and their amplitude, which determines the volume or loudness of the sound. Human hearing is typically sensitive to sound waves with frequencies between 20 and 20,000 Hz, although this range may vary depending on age and other factors.

Sound can be used for a variety of purposes, including communication, entertainment, and scientific research. For example, sound waves can be used to transmit speech or music over long distances, to create immersive audio experiences in movies and video games, or to study the properties of materials and environments.

However, sound can also have negative effects on human health and well-being. Exposure to loud or continuous noise can cause hearing damage, sleep disturbances, stress, and other health problems. In addition, certain types of sound, such as high-pitched tones or white noise, can be used to mask unwanted sounds or induce relaxation or sleep.

Understanding the properties and effects of sound is important for many fields of study, including physics, acoustics, psychology, and medicine. By studying sound waves and their behaviour in different environments, researchers can develop new technologies and techniques to improve communication, entertainment, and health outcomes.