Why does glass break?
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Answer: Stress exceeds molecular bonds
Stress exceeds molecular bonds ✓ — Correct! Glass is brittle because its molecules are locked in a rigid, amorphous structure. When force creates stress (like impact or bending), it concentrates at tiny surface flaws. Once stress exceeds the strength of molecular bonds, cracks propagate rapidly through the structure. Unlike metals that bend, glass can't deform plastically - it just breaks! That's why even small scratches weaken glass significantly.
Air pressure crushes it — Wrong. Normal air pressure doesn't crush glass. Glass breaks when applied force creates internal stress that exceeds the strength of bonds between its molecules.
Temperature melts the structure — Wrong. Glass breaks from mechanical stress, not melting. While extreme heat can soften glass, typical breaking happens when stress overcomes the molecular bonds holding the rigid structure together.