There are many ways that tensions can arise, at least when discussing materials science. Cracks in concrete are a common example, but any catastrophic failure in a material is often due to some stress that it could not withstand. If you want to see those stresses before they cause damage to the underlying material, check out this DIY polariscope that can look at internal stresses in glass and other clear objects.
The polariscope takes its name from the fact that it uses polarized light to view the internal structure of a transparent object such as glass. When the polarized light passes through glass in a certain way, the stresses appear as lighter areas thanks to the strained glass bending the light back into view. This one is made with a polarizing filter placed in front of an LCD screen to display a completely white image. When glass is placed between the screen and filter, no light is seen through the polariscope unless there are voltages in the glass. Even applying a force to an otherwise unloaded glass tube can exhibit this effect, and [Advanced Tinkering]the creator of this project, has several other creations that show this effect in striking detail.
The effect can also be seen as colored areas in other plastic materials. It’s an interesting tool that can help anyone who often works with glass, but it’s also interesting in itself to see clues left behind during the manufacturing process of various household items. We’ve seen some other research methods to determine how other household items are also mass-produced, such as this project breaking down the injection molding process.
This post Voltages revealed with a polariscope
was original published at “https://hackaday.com/2022/04/01/stresses-revealed-with-a-polariscope/”
