PADI Divemaster Certification Practice Exam

Is it true that sounds travel faster in water due to its density?

1. True

2. False

3. Only at certain temperatures

4. Only above sea level

The correct answer is: True

Sounds do indeed travel faster in water compared to air, and this is primarily attributed to the density and elastic properties of water. In denser mediums like water, molecules are closer together than in air, which allows the sound waves to transmit their energy more efficiently. As the molecules vibrate, they pass this energy to adjacent molecules, leading to a quicker propagation of sound. The speed of sound in water is approximately four times greater than in air. In water, sound travels at about 1,480 meters per second, while in air, it travels at roughly 343 meters per second at room temperature. This phenomenon is not only due to density but also how water's physical properties allow sound waves to move through it. Factors such as temperature, salinity, and pressure can affect sound speed, but the fundamental principle remains that water's density contributes to the higher speed of sound compared to gases. While the other options mention conditions that may influence sound travel in water or imply limitations, they do not negate the fundamental fact that sound travels faster in water because of its density. This foundational principle about sound propagation is key to understanding underwater acoustics, which has important applications in diving, marine biology, and environmental monitoring.