During Open House, we invite the public to campus for a day of hands-on science experiments, demonstrations, and conversations with some of the world’s leading scientists in the Earth, environmental, and climate sciences. Visitors toured the labs and crowded around demonstrations, often jumping in to help. They simulated volcanic eruptions, listened to earthquakes, and examined tiny fossils through microscopes in the Core Repository. The Dyhrman Lab brought out a rainbow of microscopic phytoplankton and explained why, when you take a breath, you should thank a phytoplankton. Marc Spiegelman used a bathtub filled with a cornstarch concoction to show how rocks inside the Earth could behave as both flowing and solid, viscous and brittle. Scientists also led geology tours on campus and a dendro eco-hike to explore Lamont’s forest history through tree-ring analysis, and they gave a series of talks about the latest research on topics including extreme weather, the planet’s changing ice, and earthquakes. This video created by Columbia University's Robert Branch, Rudy Dias and Rae Paul offers a snapshot of the day's events.