How can sound waves uncover hidden flaws inside solid metal? 🤔 Professor Rachel Edwards (University of Warwick) demonstrates how ultrasound can detect tiny defects in railway tracks - keeping travel safe for millions every day. 🚆 This innovative research combines physics, engineering, and creativity to make the invisible visible - and shows the real-world impact of science in action. With thanks to Martha Turvey for the ultrasound footage. 🔍 Explore the miniverse's greatest questions with ins