> The Eiffel Tower becomes 15 centimeters taller in the summer, due to whichphenomenon?And the answer: thermal expansion. Structure of the Eiffel Tower, © SETE_AlexandreNestoraStanding at 324 meterstall, the exact height of the Eiffel Tower can change depending on the season.When the hot summer sun beats down on it, thermal expansion causes the metal toexpand. But once the sun sets, the temperature decreases and the metalcontracts.When an object is heated, its particles gain kinetic energy, consequently movingfaster until they take up more space. Most large metal structures (such as theEiffel Tower) are constructed with this principle in mind, so they can expandand contract a little without breaking. Changes in temperature work the opposite way too – in the cold winter months,metal can contract and shrink finitely. When it heats back up again instructures like train tracks, warping and disfiguration can occur. In fact, thisphenomenon resulted in 190 train derailments during 1998–2002 in the UnitedStates alone.Thermal expansion can also occur in glass structures. Glass is a poor conductorof heat, so when hot water expands only a part of a glass material, it bendsuntil it breaks, either cracking completely or forming fissures across itssurface. To learn more about the laws of thermal expansion, check out the video below.