whistle

Depending on its dimensions, the cylinder will ring with radio waves of a specific frequency, just as a bottle will whistle with sound waves of a set pitch if you blow across its mouth.

The research team also obtained sound recordings of original Aztec death whistles as well as from handmade replicas.

"I took a deep breath and waited for the whistle, and as Tony told me, I took it with my left foot."

As the final whistle was blown, there were some small sporadic boos around the stadium but that was a token gesture.

Ikitau and Wright completed the rout as many Welsh fans left early while there some boos from sections of the home crowd at the final whistle.