Lord Kelvin was one of the greatest physicists of the nineteenth century — he laid the transatlantic cable, established absolute zero, and formulated the second law of thermodynamics. He also declared that heavier-than-air flight was impossible, called radio communication a fantasy, and calculated the Earth's age at a fraction of its actual value. His career is both a monument to scientific achievement and a cautionary tale about the limits of even the finest minds.

This episode traces Kelvin from his Belfast prodigy childhood through the thermodynamic breakthroughs, the transatlantic cable, and the famous wrong predictions that show genius has boundaries.

• The prodigy childhood — university at ten, professor at twenty-two
• The absolute temperature scale and the second law of thermodynamics
• The transatlantic cable a ...