How is the ultrasonic frequency calculated? The speed of sound in solids is also different. After repeated measurements, it is found that sound waves propagate in solids in two forms: longitudinal waves and transverse waves, and the wave speeds of these two waves are also different. For example, in stainless steel, the longitudinal wave speed is 5790 meters/second and the transverse wave speed is 3100 meters/second. The stainless steel is made into a rod shape, and the longitudinal wave speed in the rod is 5000 meters/second. Among metals, beryllium is an expert at transmitting sound. In a rod made of beryllium, the longitudinal wave speed of sound waves reaches 12,890 meters/second, which is 38 times that of atmospheric sound. Polyethylene plastic has poor sound transmission ability. The longitudinal wave speed in the polyethylene rod is only 920 meters/second, which is not as fast as the speed of sound in water. Soft rubber is very elastic, and sound waves cannot move in it. The speed is only 30-50 meters/second, which is not as fast as the speed of sound in the air!
