Structures That Grow in Summer

The Eiffel Tower is about 15 cm taller on a hot summer day than on a cold winter night. Pick a structure and a temperature swing and see how much it grows (the drawing exaggerates it).

MaterialsThermal expansionJust for fun

Inputs

Input examples

Use the temperature of the structure itself: dark steel in direct sun can get 20 °C hotter than the air.

Height or length

Expansion coefficient α (10⁻⁶ per °C) — steel and wrought iron about 12

Winter temperature (°C)

Summer temperature (°C)

Exaggerate the drawing (×)

Breathing Buildings

Large structures are never quite the same size. The Eiffel Tower, made of wrought iron, grows about 12 millionths of its height for every degree it warms — some 15 cm between winter and a hot summer day, and it even leans slightly away from the sun as one side heats up.

Engineers design for it: long bridges rest on sliding bearings and have toothed expansion joints in the road, and skyscraper facades have flexible seams. Without them the structure would push against its own supports with enormous force.

~15 cmEiffel Tower, summer

sun sidegrows more

jointslet bridges breathe

bearingsslide as it grows

Winter vs. Summer

exaggerated

winter

summer (growth exaggerated)

Result

Enter the values above

Key Relations

Growth

The same linear expansion as on the first tab, applied to the whole height.

Example:

Per Degree

How much the structure grows for every degree it warms up.

Example:

Sources & Verification

References

D. Halliday, R. Resnick & J. Walker, Fundamentals of Physics, 10th ed., Wiley, 2014 — Ch. 18 (Temperature, Heat, and the First Law of Thermodynamics).