Which medium has the slowest speed of sound among air, water, and metals?

Which medium has the slowest speed of sound among air, water, and metals?

• A. Air
• B. Water
• C. Metals
• D. Wood

Answer: (A)

The speed of sound depends on how easily a medium can transmit a pressure change, which relates to its stiffness and density. Gas contains particles far apart and is relatively easy to compress, so the pressure disturbance moves slowly. In liquids, the medium is more stiff and density is higher, so sound travels faster. In most solids, especially metals, the material is very stiff and transmits vibrations quickly, making sound travel even faster. Among air, water, and metals, air has the smallest ratio of stiffness to density, so it transmits sound the slowest. That’s why sound speeds up significantly when moving from air into water and then into metals.

The speed of sound depends on how easily a medium can transmit a pressure change, which relates to its stiffness and density. Gas contains particles far apart and is relatively easy to compress, so the pressure disturbance moves slowly. In liquids, the medium is more stiff and density is higher, so sound travels faster. In most solids, especially metals, the material is very stiff and transmits vibrations quickly, making sound travel even faster. Among air, water, and metals, air has the smallest ratio of stiffness to density, so it transmits sound the slowest. That’s why sound speeds up significantly when moving from air into water and then into metals.