The earliest known musical instruments date back to the Upper Paleolithic age and included instruments made from materials like wood, bone, and animal skins. Modern musical instruments are typically grouped into families based on their sound production method, such as strings, woodwinds, brass, and percussion. String instruments produce sound through vibrating strings that are plucked, bowed, or struck, woodwind instruments use air blown through a reed or opening to create vibration, brass instruments involve buzzing the lips into a mouthpiece to make air inside the instrument vibrate, and percussion instruments are sounded by hitting, shaking, or scraping.