He recast physics in terms of energy. Terms he introduced into physics include thermodynamics, electrical capacity, energy, kinetic energy, absolute temperature, simple harmonic motion, magnetic permeability, magnetic susceptibility, stress over strain, bulk modulus and vortex-sheet
Between 1858 and 1866, he laid the transatlantic telegraph cable, an epic undertaking involving huge practical difficulties and a House of Lords enquiry, for which he was knighted. He invented the inkjet printer (the 'siphon recorder') as the receiving and recording mechanism needing least signal power - the only moving part is the ink. The telegraph cable shrank the world dramatically and started the globalisation of information.
He invented the compass for iron ships, overcoming the ship's permanent and induced magnetism. He worked over twenty years to refine the accuracy of units of electrical measurement, defining the modern ampere, Volt, ohm and others.
Kelvin was the first to calculate the ages of the earth and of the sun, by considering all known energy sources and erosion rates. Knowing about neither radioactivity in the earth's core nor nuclear fusion that powers the sun, his results were huge underestimates, causing uproar amongst evolutionists.
He developed the basis of absolute zero, and a unit of temperature measure is named after him. In total, he produced 661 scientific papers and 75 patents and was the first UK scientist to be elevated to the House of Lords.