Why are there time zones on Earth?
Show answer & explanation
Answer: Earth rotates, sun appears to move
Sun rises everywhere simultaneously — Wrong. Sun doesn't rise everywhere at once. Earth rotates eastward, so eastern locations see sunrise first—time zones coordinate this.
Earth rotates, sun appears to move ✓ — Correct! Earth rotates 360° in 24 hours = 15°/hour. As Earth rotates eastward, different longitudes face the sun at different times. Without time zones, noon (sun highest) would occur at different clock times everywhere—impractical! 24 time zones (roughly 15° wide) standardize local time. Noon is approximately when sun is highest. Time zones have political boundaries (not exact meridians). Coordinated through UTC (Coordinated Universal Time)!
Countries set their own times — Wrong. Countries do choose time zones, but zones exist because Earth's rotation means different places face the sun at different times.
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