Today we're winding up our soil science experiment by seeing how much water remains in the root zone mix (and thus, available for plants to use) after a rainstorm. We'll also add another five inches of water to the system to compare how quickly it drains into the wet soil versus how quickly it drained into the dry soil.
But first, we're stymied by captive air--because we're conducting the experiment in a test tube and not in nature, we've got some trapped air that's preventing the soil from draining. So...out comes the drill!
A couple days later, we check in again and see how the air has returned to the pore space previously occupied by water.
After a third rainstorm, the ground is pretty well-hydrated. Does this make the latest rain drain faster or slower?
Phil wraps up the demonstration with some thoughts about why severe thunderstorms that come after a week of dry weather do nothing to help our plants and lawns. He also discusses how these soil profiles were selected for Schenley Plaza and Mellon Park.
Thanks for watching! We hope to have more science-themed demonstrations in the future. If there's ever something about the parks you're curious about, drop us a comment and we'll try to answer your questions!