The mechanical device used to convert sound waves into electrical signals is called a microphone. Microphones work by capturing sound waves—vibrations in the air—and converting these physical movements into electrical energy that can be amplified, recorded, or transmitted. There are various types of microphones, including dynamic, condenser, and ribbon microphones, each suitable for different applications in music, broadcasting, and filmmaking. Their invention revolutionized communication and recording technologies, leading to significant advancements in music production, telecommunications, and public speaking.