Ever wondered why rivers take such meandering paths on their way to the sea? Minute Earth explains in this short video:
This process goes on all the time: unless the banks are reinforced (as they are usually as they flow through big cities), the river's path will keep on changing over time. Vox recently featured this animated gif (from the Time Timelapse site, which has several other cool animations), showing the path of Peru's Ucayali River from 1982 to 2012.
Incidentally, much the same process is behind the formation of river deltas. As the river reaches the sea and slows down, it deposits sediment. The river's shifting position acts much like a random walk, and the sediment creates the triangular shape of the delta.
That's all we have for this week. Join us back here on Monday for more from the Revolutions blog.