what is the speed of sound

The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. The speed of sound depends on the temperature and composition of the medium through which it travels. At 20°C (68°F), the speed of sound in air is about 343 meters per second (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn). The speed of sound in air at sea level, assuming an air temperature of 59 degrees Fahrenheit (15 degrees Celsius), is 761.2 mph (1,225 km/h). The speed of sound in dry air at 20 degrees Celsius is 343 m/s. The speed of sound varies from substance to substance, with sound traveling most slowly in gases, faster in liquids, and fastest in solids. For example, while sound travels at 343 m/s in air, it travels at 1,481 m/s in water (almost 4.3 times as fast) and at 5,120 m/s in iron (almost 15 times as fast). In an exceptionally stiff material such as diamond, sound travels at 12,000 meters per second (39,000 ft/s), which is about 35 times its speed in air and about the fastest it can travel under normal conditions.