Follow a turning river disc
A city webcam made a surprising Maine ice formation observable over time. Compare the recorded motion with the scientists’ competing mechanism discussions.
What to keep in mind
The city sequence is accelerated and its sampling interval is not authenticated here. Laboratory ice discs and this river formation have different scales and conditions.
Keep the bank fixed
Follow a recognisable detail on the ice rim against the riverbank. Which motion can you describe without knowing the time-lapse sampling interval?
Look for changes at the edge
Watch where the rim approaches the bank and surrounding ice. What changes would support rounding through contact rather than a perfectly formed initial disc?
Compare the proposed mechanisms
What water-temperature or current measurement would distinguish a melting-driven mechanism from river flow here? Record why the webcam cannot supply it alone.