Physics
How Thermal Expansion Changes the Height of the Eiffel Tower
Quick fact
The Eiffel Tower's height changes by about 15 centimeters (6 inches) between the coldest winter and hottest summer days, because the iron expands when heated and contracts when cooled.
Why this is interesting
The Eiffel Tower stands over 300 meters tall in winter, yet in summer it grows by up to 15 centimeters—taller than a pencil lying on its side. How can a solid iron structure simply stretch with the seasons?