Speed of sound Facts for Kids

U.S. Navy F/A-18 traveling near the speed of sound. The white halo consists of condensed water droplets formed by the sudden drop in air pressure behind the shock cone around the aircraft (see Prandtl-Glauert singularity).

The speed of sound is 1,235 kilometres (767 mi) per hour or 330 metres (1,083 ft) per second in dry air in room temperature. Sound moves faster through liquids and solids than air, since liquids and solids can be pushed together more. Sound cannot travel through a vacuum, which is a space without any air or matter. The speed of sound is affected by temperature. It travels slower at low temperatures, for example in the stratosphere.

You can calculate the speed of sound like this:

$a = \sqrt{\gamma*R*T}$

Where: $\gamma$ is the ratio of specific heats (1.4 for air) R is the gas constant ( $287 N*m/kg*K$ for air) T is temperature (in Kelvins)

The speed of sound is also known as Mach 1. Things that go faster are supersonic.

Images for kids

Pressure-pulse or compression-type wave (longitudinal wave) confined to a plane. This is the only type of sound wave that travels in fluids (gases and liquids). A pressure-type wave may also travel in solids, along with other types of waves (transverse waves, see below)
Transverse wave affecting atoms initially confined to a plane. This additional type of sound wave (additional type of elastic wave) travels only in solids, for it requires a sideways shearing motion which is supported by the presence of elasticity in the solid. The sideways shearing motion may take place in any direction which is at right-angle to the direction of wave-travel (only one shear direction is shown here, at right angles to the plane). Furthermore, the right-angle shear direction may change over time and distance, resulting in different types of polarization of shear-waves

Speed of sound facts for kids

Images for kids

See also