Why does a vibrating guitar string not sound as loud when it is mounted on a work bench?

Question

Why does a vibrating guitar string not sound as loud when it is mounted on a work bench as it does when mounted to a guitar?

Answer 1

the guitar is hollow which allows sound waves to travel. The work bench is not

Answer 2

Notice the sounding box (I think thats the right term) on the guitar.  The sound waves bounce around on the box, constructively interfere with each, and then leave the box with more intensity.  On a work bench the sound waves just dissipate without amplifying on each other.

Answer 3

The work bench is made of a large chunk of solid wood - so the vibrations from the string haven't enough energy to make the large mass off wood vibrate with a big enough amplitude to be heard very loud.

If the string is mounted on an acoustic guitar the wood is very thin so the string can make this vibrate with a bigger amplitude - these vibrations  in turn are  passed onto the air inside the body of the guitar which then resonates with a bigger amplitude and so is louder again.