# What is the name for the whistling “musical” sounds that change stepwise in pitch when a hollow tube is spun like a lasso?

You have likely heard those sounds, science museums sometimes sell Flexible plastic tubes you can whirl like a lasso. The air rushing by the end of the tube causes these sounds, which are admitted in discrete "notes".

What physical process causes that strange segmenting of the sound into a discrete "scale"? Sounds almost pentatonic.

Know a scientific name for that effect?

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Note, we live on a world where an iPad can substitute words for you, in trying to repair a typo, and make you appear as if you don't know the difference between a sound being emitted or "admitted." Ugh! – estephan500 Oct 28 '12 at 9:31

The tube is behaving like an open pipe, and this has a series of natural resonant frequencies corresponding to a wavelengths of $2L/n$, where $L$ is the length of the pipe and $n$ is an integer taking the values 1, 2, 3, 4 etc. The sounds you hear correspond to these resonances. Which resonance is the loudest depends on how much energy you're putting in i.e. how fast you swing the pipe.