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The Eiffel Tower can stand up to about 15 centimetres taller in summer than in winter, because its iron expands in the heat.

Structural engineering (thermal expansion)

TechnologyScience

The story behind the card

Iron expands as it warms and shrinks as it cools, and the tower's frame contains 7,300 tonnes of it, 18,038 pieces joined with 2.5 million rivets. Sunlight rarely heats it evenly: on a clear day the side facing the sun expands more than the shaded side, so the top can lean up to 18 centimetres away from the sun, returning as the air cools. Wind moves it too, swaying the top by up to 9 centimetres. Gustave Eiffel's company built the tower for the 1889 World's Fair in Paris. To keep the iron from rusting, it is repainted every seven years with about 60 tonnes of paint, and it has been completely repainted at least 19 times.

Türkçe oku
Eyfel Kulesi yazın kışa göre 15 santimetreye kadar uzayabilir, çünkü demiri sıcakta genleşir.

Demir ısındıkça genleşir, soğudukça büzülür. Kulenin iskeleti 7.300 ton demirden oluşur: 18.038 parça, 2,5 milyon perçinle birleştirilmiştir. Güneş kuleyi nadiren eşit ısıtır. Açık bir günde güneşe bakan yüz gölgedeki yüzden daha çok genleşir ve kulenin tepesi güneşin tersine doğru 18 santimetreye kadar eğilir; hava serinleyince yeniden yerine döner. Rüzgâr da tepeyi 9 santimetreye kadar sallar. Kuleyi, 1889 Paris Dünya Fuarı için Gustave Eiffel'in şirketi inşa etti. Demirin paslanmaması için kule yedi yılda bir yaklaşık 60 ton boyayla boyanır; bugüne kadar en az 19 kez baştan sona boyandı.

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Background reading: Eiffel Tower
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