TechnologyARMY on Instagram: "This kid recreated the principle behind Thomas Edison’s phonograph — using nothing but simple materials. 🧠 Here’s how it works: 🎙️ Sound creation: The voice hits a thin membrane inside the cup, making it vibrate. 🔊 Mechanical motion: The vibrations move a needle or wire that transfers those movements. 💿 Playback: The needle scratches or vibrates a rotating disc, reproducing the sound without electricity. It’s a mechanical sound experiment — no microphone, no spe