The Eiffel Tower Grows Taller In Summer Heat

The iconic Eiffel Tower is never exactly the same height twice. Built from puddled iron, the structure responds to temperature changes through a physical phenomenon called thermal expansion. When temperatures rise in summer, the iron expands and the tower grows taller. Engineering calculations show that a 100-meter iron bar expands by about 12 centimeters when heated by 100 degrees Celsius. While the Eiffel Towers lattice structure behaves somewhat differently, specialists have measured a real-world seasonal variation of 12 to 15 centimeters. The sun creates another interesting effect. Since it only hits one of the four sides at a time, that side expands more than the others, causing the tower to tilt slightly away from the sun. The top of the tower can move in a circular curve measuring approximately 15 centimeters in diameter as the sun tracks across the sky. In winter, the opposite occurs as the metal contracts and the tower shrinks by the same amount. These changes are imperceptible to visitors but demonstrate how even massive steel structures are responsive to the natural environment. The same principles of thermal expansion apply to bridges, railway tracks, and other large metal constructions.