What are some examples of failed experiments that produced valuable information?

Several experiments have failed yet yielded valuable insights. For instance, Thomas Edison’s numerous unsuccessful attempts to create a viable light bulb led to the eventual development of a practical design, demonstrating the importance of perseverance in innovation. Similarly, the Apollo 1 tragedy, while devastating, prompted significant safety reforms in NASA's protocols, ultimately enhancing the safety of future space missions. Additionally, the discovery of penicillin by Alexander Fleming resulted from an accidental contamination of Petri dishes, illustrating how unexpected outcomes can lead to groundbreaking advancements in medicine.