15th April 1995. The Secret of Waves.
It must be frustrating for one to make a great discovery only to be ignored in one’s lifetime, when one had discovered a bizarre water-wave that no-one believed should exist. It was only later that the true nature of the discovery was understood.
It wasn’t until modern computers in the 1960s, that the significance of John Scott Russell’s discovery was recognized in physics, electronics, biology, and especially in fibre-optics which has lead to the modern study of Solitons.(1)
In fluid mechanics the Wave of Translation, is now called Russell’s Solitary Wave and was the subject of an article in The New Scientist whose heading today in 1995 was called: ‘The Secret of Everlasting Life’.
The article related to the solitary wave, which John Scott Russell dubbed the Wave of Translation, a non-linear wave propagation.
In 1834 Russell, involved in ship hull design, was observing a boat being drawn along ‘rapidly’ by a pair of horses, when the boat suddenly stopped. He noticed that the ‘bow wave continued forward at great velocity assuming the force of a large solitary elevation, a well-defined heap of water which continued along the channel apparently without any change of force or diminution of speed’.
He followed the wave on horseback as it rolled at about 8 mph, but after half a mile lost it.
Russell at the time was conducting experiments to determine the most effective design for canal boats on the Union Canal at Hermiston, Edinburgh, and shows how by accident great discoveries are made.
Normal waves oscillate, But Russell’s Wave of Translation depended on its size and width and depth of water and is incredibly stable for 80 miles. Also unlike normal waves they never merge. So a small wave is overtaken by a larger, rather than they combine.
If wave is too big for depth of water it splits into two: one big wave and one small.
It was eventually thought that if water could be made to travel so far what about light waves?
Today most advanced fibre-optic communications use stable pulses of light identical to Russell’s waves now called a soliton, (from solitary waves), to carry masses of information over 100s of miles of fibreglass.
Thus by accident, was laid the foundations of modern telecommunications.
(1) Solitons are by definition waves which are unaltered in shape and speed by collision with other Solitons, so Solitary Waves on water are ‘near Solitons’.
This is because after the interaction of two (colliding or overtaking) Solitary Waves, they are changed slightly in Amplitude and some Oscillatory residue left behind.
ADDENDA ON WAVES:
Transverse waves are where the medium is dispersed in perpendicular direction to energy transported, as in light and most water waves. Analogy as in the rope when ‘cracking a whip’
Longitudinal waves, as in sound, are where the medium is dispersed in direction of energy transported without permanently transporting matter, as in a stretched-spring ‘slinky’.
Ref: Report on Waves (meeting of british Advancement for Science, York Sept 1844 (Lond 1845 pp 311-90 Plates XLVII-LVII).
Ref: Pic Ref: google images/rspb.org.uk.
Ref: hw.ac.uk Scott Russell and solitary wave.
Ref: Links-JS Russell-external links -re creation of solitary wave.