Just discovered the soliton wave thing. Have long been interested in physics of the Slinky…I’ve heard that Slinkys in motion are transmission waves–which I understand intuitively but am not sure if it was said as a metaphor.
Any help?
Thanks, Leo
You can form an approximate soliton by plucking a stretched-out slinky. This would be a longitudinal wave. The soliton would only be approximate because the medium is dispersive – if you watch the wave travel it will start out localized and then slowly spread out.
I don’t know what a ‘transmission wave’ is. Do you mean ‘transverse’? If you wiggle a slinky up and down you will get a transverse wave. If you push it or pluck it in the direction between it’s two ends, you will get a longitudinal wave.
I don’t believe so. a soliton is a case of a traveling wave form that maintains itself 9or comes apart and re-forms itself) by the balancing of dispersive and nonlinear effects. I haven’t studied them much myself, but the standard lore is that they were first observed in waves in a canal in holland back in the 17th century. nowadays the effect is often in fiber optics, where nonlinear effects only become important at high intensities, so you generally need high popwer, short duration laser pulses. Because they don’t disperse with time and distane, they’re ideal for transmitting information over long distances without loss.
Obviously, the ones observed in the canal didn’t require hih “intensity”, but I suspect the non-linear effects in a slinky are pretty small. Just because you can see a single "bump’ propagating in a slinky doesn’t mean that it’s a soliton – you can get the same effect by superposition of normal modes, which is how such waves in slinkies, rubber bands, ropes, and strings are typically explained in undergraduate wave courses. You don;t see the disperse over a single transition because the path is too short.
The Soliton wave was first described scientifically by John Scott Russell in 1834 based on his observations of them on a canal just outside Edinburgh.
Somewhere I have photos of the commemorative plaque on one of the bridges over the canal.