The speed of sound is dependent on the medium through which it is traveling. Under typical conditions, at sea level, sound travels 1,225 kilometers per hour, or 340.29 meters per second.
Because sound is essentially the result of molecules colliding with one another, the more dense the medium, the faster the sound wave travels. Sound travels much faster through water than it does through air. In a lighter-than-air gas, such as helium, sound travels much slower because the molecules are spaced further apart. Sea animals take advantage of the increased speed of sound in water to detect their surroundings via sonar.