How to Quickly Break a Car Window?

[SanAlivia]

Direct the safety hammer to the lower corner of the glass and strike forcefully, and the window will shatter quickly. The main principles are as follows: 1. On one hand, tempered glass is a prestressed structure. After being forged at high temperatures, tempered glass is cooled by air pressure the moment it exits the tempering furnace. While the interior of the glass is still expanding outward, the surface has already cooled. This creates two forces: an outward tensile stress and an inward compressive stress. The corners of tempered glass are the areas most prone to stress concentration, making them structurally the most vulnerable to damage under the same external force. 2. On the other hand, from an energy perspective, tempered glass can be imagined as an elastic membrane. When subjected to external force, the glass deforms, with the central area bulging outward momentarily, absorbing some of the energy and making it harder to break. However, striking the four corners, where the glass is fixed by the window frame and undergoes minimal deformation, maximizes the impact energy, making it easier to shatter the glass.