Why do airplane windows have tiny holes?
Show answer & explanation
Answer: Equalize pressure between panes
Equalize pressure between panes ✓ — Correct! Airplane windows have 3 panes: outer (structural), middle (with tiny hole—breather hole), inner (scratch shield). Cabin pressurized to ~8,000 ft equivalent; outside ~35,000 ft = huge pressure difference. Breather hole equalizes pressure between middle and inner panes—outer pane bears full pressure load. Also prevents moisture condensation between panes (would fog view). Hole ~0.5mm diameter. Redundancy: if outer pane fails, middle pane holds pressure!
Prevent condensation buildup — Wrong. Hole does prevent condensation, but primary purpose is pressure equalization—outer pane bears full cabin pressure load safely.
Emergency pressure release — Wrong. Hole does allow pressure relief, but designed function is equalizing pressure between panes, not emergency release.