Flat vs. Round Earth Calculator
Prove the Earth is round with three scientific experiments: sunset observation, object hiding, and shadow measurements
Choose Your Experiment
Sunset Twice Experiment
Move upward quickly after sunset to see the sun again! This proves Earth's curvature by getting ahead of the horizon's shadow.
Typical sunset: 120-300 seconds
Second Sunset Results
Formula: t = 8 × √h (shadow movement time)
✅ You can see 4.8% of the sunset again - proving Earth is round!
Earth Facts
Circumference
40,008 km (polar) / 40,075 km (equatorial)
Curvature
8 inches per mile (12 cm per km)
First Measured
Eratosthenes, 240 BC, within 10% accuracy
Experiment Tips
Clear horizon and calm weather are essential
Use binoculars or zoom camera for distant objects
Shadow measurements work best at solar noon
Greater distances give more pronounced effects
Understanding Earth's Curvature
Why These Experiments Work
These experiments demonstrate Earth's spherical nature through observable phenomena that only occur on a curved surface. Each test provides measurable evidence that contradicts flat Earth models.
Historical Context
- •Ancient Greeks knew Earth was round (5th century BC)
- •Eratosthenes calculated circumference (240 BC)
- •Sailors observed ships appearing hull-first
- •Different constellations visible at different latitudes
Scientific Method
These experiments follow proper scientific methodology: observe, hypothesize, test, and conclude based on evidence.
What About Flat Earth Claims?
- Sunset twice: Impossible on a flat plane
- Hidden objects: No curvature to hide behind
- Shadow differences: Would require very close sun
- Time zones: All locations would see sun simultaneously