CBSE Class 9 Answered

Sound travels faster through warm air than through cold air. This is to be expected because the faster-moving molecules in warm air bump into each other more often and therefore transmit a pulse in less time. For each degree rise in temperature above 0 degrees C, the speed of sound in air increases by 0.6 meters per second. In water, sound travels about four times as fast as it does in air, while in steel, the speed of sound is about fifteen times as great as in air. The air is denser in cold weather so sound waves travel more efficiently through the air. With the molecules closer together they have a greater chance of colliding with other molecules to transfer the sound.