Hostelworld.com
Eiffel Tower, Paris (France)
In addition to being a point of reference, a communications tower and a symbol of Paris, the Eiffel Tower is also a giant thermometer.
A Torre Eiffel It was not always called Eiffel Tower. Originally it was nicknamed 300 meter towera 300 meter tower.
This name was proposed by engineers Maurice Koechlin and Émile Nougier to Gustave Eiffel, who supervised the construction of the tower.
The name indicated the desire to build something extraordinary, a technological feat that would establish a new record of height.
However, with the increased temperatures During the summer months, the Eiffel Tower becomes even higher than your original project.
A light iron structure
The Eiffel Tower was erected at the World Fair of 1889 to commemorate the centenary of the French Revolution.
Eiffel chose the cast iron for his construction, a material he knew well and had used in previous projects with good results.
This ferrous material is capable of withstanding high tension levels, which allowed the construction of a large and very light tower that would be protected from the horizontal forces of the wind.
To get an idea of the tower’s lightness, its weight of 7300 tons approaches the weight of air volume contained in it-about 6300 tons.
The Eiffel Tower is designed to be a privileged point of observation as well as a base for broadcasting.
Structures like it grow when the material temperature increases. However, on the contrary, for example, bridges, which behave more complexly, the Eiffel Tower mainly records growth and vertical contraction due to temperature changes.
This phenomenon is known as thermal expansion.
How much did the Eiffel tower grow?
We know that most solids expand when the temperature increases and contracts when it decreases. This is due to the fact that increased temperature causes higher agitation in atoms, which leads to an increase in the average distance between them.
Depending on the nature of the connection, different types of solids experience greater or lower growth, which engineers have to record very carefully. Ceramics and glass, with stronger connections, expand less than metals, which in turn expand less than polymers.
So how can we estimate the amount of movement in a solid? When the elements are straight – as is the case with most public works and architecture, where the beams and bars predominate – the movement is proportional to three parameters: the element length, the variation of its temperature and the coefficient of dilation of the material.
The inplayed iron used in the Eiffel Tower and its steel components have a coefficient of about 12 × 10-⁶ (° C) -¹, which means that an iron bar with one meter in length expands 12 × 10-⁶ meters when the temperature increases a degree. That is less than the thickness of human hair.
Now, let’s do the math. Let’s calculate how simple metal bar of 100 meters long expands when the temperature varies at 100⁰C – the approximate range experienced by the Eiffel Tower.
The calculation is simple. If a bar of one meter dilates 0.000012 meters when the temperature rises a degree, a 100 meter bar is dilated 0.12 meters when the temperature rises 100 degrees. And a 300-meter bar would widen three times more: 0.36 meters. I.e, 36 cm. It is a remarkable difference.
It is evident that a simple bar does not behave the same as a tower consisting of over 18,000 riveted iron pieces oriented in all directions. Also, the sun always shines in one of its sides. This means that one of its faces grows more than the others, causing a slight curvature in the tower, as if it were leaning to the sun.
Experts estimated that Eiffel Tower grows between 12 and 15 centimeters When compared to its size on cold winter days with the hottest summer days.
This means that, besides being a point of reference, a communications tower and a symbol of Paris, the Eiffel Tower is also, in fact, a giant thermometer.
