This drinking glass comes from former East Germany (DDR) and was made using chemical hardening. Regular glass is placed into a hot potassium salt bath, where sodium ions on the surface are replaced by larger potassium ions. This creates compressive stress on the surface and tensile stress inside the glass, making it much stronger than normal glass. This is the same ion-exchange process used in modern chemically strengthened glasses, such as smartphone display glass (e.g. Gorilla Glass). Sounds impressive… but how strong is it really? In this video we test: DDR chemically hardened drinking glass Regular modern drinking glass Finnish “unbreakable” plastic glass Swedish IKEA glass Hockey pucks from different countries All of them vs our hydraulic press. Some survive longer than expected. Some are… disappointing. ⚠️ This video is for entertainment and educational purposes only. Do not try this at home.