How is sound made why does it travel faster through solid elements and what is its speed?

Sound is a transverse wave made by particles banging into one another. (thus sound cannot travel in a vacuum)

In air (a gas), the particles are a long way apart so it takes longer for them to collide with one another to carry the sound.

In a solid, say a bar of metal, all the particles are jammed really close together, so if you bang one end of the bar, the wave will travel quickly down the length of the bar.

Sound travels at around 330m/s in air, and how fast it goes in solids depends on the properties of the solid, but I think for most metals it is very roughly around 600m/s

Hope this helps.