It seems crazy, but scientists found out that sonic waves have mass. Usually people have believed that sonic and sound waves had no mass. That they just changed in different circumstances, like water and air. New research shows that sonic waves actually do have mass. Things called phonons are part of the waves that make the waves travel. Scientists from Carnegie Mellon believe that it can be measurable, but would have a negative mass. This is interesting and is proof of how wacky this world is.