Have you ever seen a plane before you could hear the sound of its engines? Or seen lightning before you heard the thunder that it created? Sound travels slower than light travels - that is why you can see things before you can hear them. Sound, like other waves you’ve learned about, travels at different speeds in different media. In air, sound travels about 335 meters per second. It takes sound about 3 seconds to travel 1 kilometer.Let’s talk about why sound travels at different speeds in different media. Think about sound waves as the vibration of molecules. If the medium is very dense, such as steel, the molecules are packed very tightly together. When one molecule moves, it quickly bumps into another, and sets it moving. Since there is more contact between the molecules, the compression wave can move much faster between them. In air, the molecules are spaced far apart, and one has to travel much more distance to get to the next. This takes more time, and the wave moves more slowly.
Speed of sound
In your own words describe how sound travels through air?
One possible answer is: when one molecule vibrates it bumps into other molecules. Since the molecules in the air are not compacted the sound takes more time to move.
