Never Pour Boiling Water on a Frozen Windshield
Thermal shock can crack your windshield. Use lukewarm water, heat from inside, or de-icer instead.
Why Boiling Water is a Bad Idea
👉 Thermal shock.
Glass expands when heated. Ice-cold glass + suddenly very hot water = extreme temperature differences in the material. The warm outer layer wants to expand, the cold interior does not.
Result: Stress fractures.
Sometimes nothing happens. Sometimes you get a spontaneous, impressive crack collection.
What Actually Works (Physics-Approved)
1. Lukewarm Water (Not Hot!)
Hand-warm is fine. It provides enough energy to melt ice without creating extreme stress.
2. Heat Inside, Scrape Outside
Warm air from inside heats the glass evenly. Ice releases because the boundary layer between glass and ice melts. Scraping then removes the rest almost effortlessly.
3. Alcohol Beats Ice (Chemistry Helps Physics)
De-icer spray or a mix of water + alcohol (e.g., isopropyl) lowers the freezing point. The ice loses its crystalline structure and turns to slush. No force needed.
4. Covering Beats De-icing
A blanket, cardboard, or windshield cover prevents the glass from losing heat to the cold night in the first place. The best physics is often: don't let the problem happen.
The Takeaway
👉 Ice wants energy. Glass hates surprises.
Apply warmth slowly, evenly, and without drama.
This is not superstition - it is material physics. And much cheaper than a new windshield.