The velocity is a measure of the distance traveled during one unit of time.
- A wave propagating in plastic during one second is travelling a specific distance
- The same wave travelling in steel instead of plastic, will go further during that same second
- Comparing the two, it is possible to see that the velocity of the wave is greater in steel than in plastic
Each material has a different ultrasound velocity. Furthermore, velocities in solid material are faster than velocities in liquids.