_______ expansion makes the Eiffel Tower taller during summers.

Thermal

The correct answer is Option (2) - Thermal

Thermal expansion refers to the tendency of materials to increase in size or volume when heated. This phenomenon occurs because heating causes the atoms or molecules within a material to vibrate more vigorously, leading to increased spacing between them. As a result, the material expands in all directions. In the case of the Eiffel Tower, which is primarily made of iron, thermal expansion plays a significant role in its height variation throughout the year. During the hot summer months, the metal structure of the tower absorbs heat from the Sun, causing its temperature to rise. As the temperature increases, the iron expands, causing the overall height of the tower to increase slightly.

Conversely, during colder periods, such as winter, the temperature decreases, causing the iron structure to contract as it loses heat. This contraction results in a slight reduction in the height of the Eiffel Tower. While the changes in height due to thermal expansion and contraction are relatively small and may not be noticeable to the naked eye, they are nonetheless significant from an engineering perspective. Engineers and architects must account for thermal expansion and contraction when designing and constructing structures like the Eiffel Tower to ensure their stability and structural integrity throughout changing environmental conditions.

Overall, thermal expansion is one of the factors contributing to the dynamic nature of structures like the Eiffel Tower and highlights the importance of considering environmental factors in their design and maintenance.