The Eiffel Tower gets taller by up to 6 inches during the summer, when the temperature reaches as high as 40°C. Extreme heat causes the metal at the base to expand, increasing the height of the 300-metre-tall tower. It also causes the top of the tower to tilt away from the sun by up to 7 inches.
One of the reasons the Eiffel Tower is still as dazzling as ever is because it adapts to its environment and all types of weather conditions: wind, cold, rain, snow, frost, heat, etc. Like any metal, puddled iron is sensitive to variations in temperature and so reacts to high temperatures in summer and low or even negative temperatures in winter.
When temperatures rise, the Tower increases in size! This is a natural physical phenomenon called thermal expansion. Heat causes an increase in volume that makes the Eiffel Tower a few centimeters taller. This expansion also causes the Tower to tilt slightly away from the sun. The sun only hits one of the 4 sides of the Tower creating an imbalance with the other 3 sides, that remain stable, thus causing the Eiffel Tower to lean. In this way, the sun’s movement over the course of a clear day can cause the top of the Tower to move in a more or less circular curve measuring approximately 15 centimeters in diameter.
Conversely, when cold winter weather arrives, the metal structure contracts and it can lose a few centimeters as well!
Suffice it to say that these changes are natural and infinitesimal and have no impact on the robustness of the structure. They are also absolutely imperceptible to visitors and observers. On the other hand, high winds can cause it to wobble or vibrate somewhat, without damaging the structure. Because the engineers at Eiffel’s company had 20 years experience designing metal viaducts, the Tower was truly (with its curved shapes and edges) designed to minimize wind resistance! But of course, when the wind exceeds certain limits we close the top floor, or even the whole Tower, to protect the public and our staff from the risks posed by turbulent weather conditions.
Credit : Tour Eiffel
Picture Credit : Google
