The Eiffel Tower can be 15 cm taller during the summer
Over its 133-year history, the famous Eiffel Tower in France has gotten taller. You want know how? Radio and television antennas. But in addition to the new equipment added to the top, the tower’s metal structure gains or loses a few centimetres throughout the year. Now how is that even possible? Well, it is simple science! The heat in summers causes its metal to expand.
The world's tallest tower for 42 years
One of the most famous attractions to visit around the world, Eiffel Tower, is a wrought-iron lattice tower in Paris, France. It is named after the engineer Gustave Eiffel, whose company designed and built the tower. But do you know why it was built in first place?
The tower was built to celebrate the centennial of the French Revolution. Its design and beauty, especially as it glows after dark, have made it one of the most visited monuments in the world.
When it was inaugurated in 1889, the Eiffel Tower, originally called "the 300 metre tower," had a total height of 312 metres. That made it the tallest tower in the world and it proudly held that title until 1931. That year, it was dethroned by New York’s Empire State Building which had a height of 381 metres.
The Eiffel Tower’s height has also not remained the same. It measures 330 metres currently including the antennas that were added at the summit in 1957, 2000 and 2022.
A few centimetres gained in summer, but lost in winter!
The beauty of this famous tower is that it stands tall and dazzling as ever sustaining all types of weather wind, cold, rain, snow, frost, heat and so on. But like any metal, puddled iron is sensitive to variations in temperature and so reacts to high temperatures in summer and low and negative temperatures in winter.
The question is why it expands in summer. Well, you must have studied something called thermal expansion in your physics class. When temperatures rise, heat gain causes all solid, liquid and gas matters to expand. So, by that principle, the hot weather makes Eiffel tower gain heat in summer which causes an increase in volume that makes the Eiffel Tower a few centimetres taller. Conversely, when cold winter weather arrives, the metal structure contracts and it can lose a few centimetres as well!
But do you know this expansion also causes the tower to tilt slightly away from the sun? The sun only hits one of the four sides of the tower creating an imbalance with the other three sides, that remain stable, thus causing the Eiffel Tower to lean.
The Eiffel Tower was once yellow!
We will tell you another amazing fact about this towering structure. Back in history at some point, it was yellow in colour. But how is it brown in colour now? Is there some science to that too?
No, the simple explanation to that is this: It has been repainted a number of times, an average of once in every seven years. When it opened in 1889, the Eiffel Tower sported a reddish-brown colour. A decade later, it was coated in yellow paint. The tower was yellow-brown and chestnut brown before the adoption of the current, specially mixed “Eiffel Tower Brown” in 1968.