sound speed!
Hi,
If you observe.. sound speed in air is 330m/s, when inliquid it is 1497m/s and in solids is 5100m/s. This varience is because sound is a mechanical wave and it badly needs a medium to propagate..(thats why sound waves doent propagate in vaccum.)
So, you know density of (gases < liquids < solids) which means molecules(medium of propagation for sound) in gases are farther from each other when compared to liquids which inturn are again farther when compared to solids.. so a molecule should carry the sound wave to the next molecule..which takes more time in gases than in liquids which inturn takes more time than solids..
hence it takes longer time to propagate in gases.. hence lower speed in gases than liquids inturn in solids..
The loss of enery is also greater in gases than liquids inturn greater than solids..
Added after 3 minutes:
In first line.. speed of sound in air , liquids, solids are only approx nos.. and the speed varies wrt temperature, density, altitude and other conditions.. check wikipedia for more info..