There are many forms of stress, at least when it comes to materials science. Cracks in concrete are a common example, but any catastrophic failure in materials can usually be attributed to unbearable stresses. If you are interested in looking at these stresses before they damage the underlying material, you can look at this DIY polarizer, which can look at the internal stresses of glass and other transparent objects.
The name of polarizer comes from its use of polarized light to observe the internal structure of transparent objects, such as glass. When polarized light passes through the glass in some way, the stress appears as a lighter area because the stressed glass refracts the light back to the field of view. This one consists of a polarizing filter placed in front of an LCD screen to display a completely white image. When the glass is placed between the screen and the filter, light cannot be seen through the polarizer unless there is stress in the glass. Even applying a force to a glass tube without pressure can show this effect, and the creator of this project [advanced repair] has several other works that show this effect in amazing detail.
This effect can also be observed in other plastic materials. This is an interesting tool that can help anyone who often uses glass, but it is also interesting in itself. You can see the clues left in the manufacturing process of various household products. For example, we have investigated how to decompose other household products.