Lake Minnewanka Experiment Proves Earth's Curvature

Testing Earth's Curvature at Lake Minnewanka

If you've ever questioned how we know Earth is curved, this experiment provides undeniable proof. Conducted at Alberta's Lake Minnewanka, the test uses precise optical measurements across 7km to detect hidden shoreline elevation. After analyzing the methodology and footage, I can confirm this is one of the most accessible real-world curvature demonstrations.

Key Experimental Parameters

The test compared visibility changes from two camera heights:

Maximum elevation: 1.5 meters above water
Minimum elevation: 10 centimeters above water
Distance to target: 7km (Aylmer Canyon shoreline)
Lens: Tamron FD zoom at 288mm focal length
Field of view: 2.48° (170m vertical coverage at target)

Camera equipment included a Blackmagic Pocket 4K in 2.6K crop mode (12.5mm × 7mm sensor). Shooting at 120fps with 180° shutter captured maximum detail. As the video creator emphasizes, these parameters were verified against satellite imagery and physical markers.

Mathematical Proof of Curvature

The experiment relies on two critical Pythagorean calculations:

Horizon Distance Formula

$$d_1 = \sqrt{H_0^2 + 2RH_0}$$
Where:

$H_0$ = viewing height
$R$ = Earth's radius (6,371km)

Hidden Object Height Formula

$$h_1 = \sqrt{(D_0 - d_1)^2 + R^2} - R$$
Where $D_0$ is total distance (7km)

For the test conditions:

Expected occlusion at max height: 0.54m
Expected occlusion at min height: 2.7m
Delta: 2.16m (≈1.3% of image height)

These calculations, credited to GitHub user Dizzib's curvature calculator, form the experiment's foundation. What makes this remarkable is how these abstract numbers translate to visible effects.

Visual Verification in Footage

The shoreline's visibility changes dramatically between camera elevations:

Key Reference Points

Tour boat at 1km distance: Served as scale reference (3m total height)
Shoreline gradient: Up to 1m elevation gain from water to forest
Red guideline markers: Represented predicted 2.2m height difference

When comparing peak vs. nadir footage:

Shoreline features disappear at low angles
Visibility changes match predicted 1.3% image height delta
The tour boat's known dimensions confirmed scale accuracy

Critical finding: The observed 2m+ occlusion delta directly corresponds to theoretical predictions for a spherical Earth. This methodology eliminates subjective interpretation.

Why This Experiment Matters

Beyond confirming curvature, this approach demonstrates how anyone can verify Earth's shape:

Validation Checklist

[✓] Use telephoto lens (200mm+)
[✓] Measure exact distance and elevation
[✓] Include scale references
[✓] Calculate expected occlusion
[✓] Compare multiple heights

For further exploration:

Dizzib's curvature calculator (GitHub): Essential for predictions
Nauticed.org curvature resources: Explains marine navigation proofs
Geodetic surveying textbooks: Detail professional-grade methods

Conclusion

This Lake Minnewanka experiment proves Earth's curvature through measurable, repeatable optics. When you see shoreline features vanish predictably as the camera lowers, you're witnessing planetary geometry in action.

Which experiment parameter do you think is most critical for replication? Share your approach in the comments.