Tensional stress is a type of force that stretches materials, causing them to elongate. It occurs when two opposing forces pull away from each other, creating tension within the material. This stress is commonly observed in structures like bridges and cables, where the materials must withstand forces that try to pull them apart. In geology, tensional stress can lead to the formation of features such as faults and rifts. When tectonic plates move apart, the resulting tensional stress can cause the Earth's crust to fracture, leading to geological changes over time. Understanding tensional stress is essential in fields like engineering and earth sciences.