“Trashcano” eruption: Pop rocks, pyroclasts, and drones
As part of the Volcanology outreach event for Earth and Space Exploration Day at Arizona State University, we asked our visitors what drives explosive eruptions? To demonstrate, we created transient eruption columns from liquid nitrogen explosions in a water-filled trashcan. These explosions are driven by the rapid expansion of liquid converting to gas – a great excuse to discuss the physics of actual volcanic eruptions. Details of the classic setup can be found here by Karen Harpp et al. We brought in a few twists:
- Added two classes of pyroclasts to the trashcano: water-filled balloons (representing denser lithics) and air-filled balloons (low-density pumice). Which should be more widely dispersed? We invited volunteers to investigate the explosion aftermath and report back to the audience.
- Handed out ‘pop rocks’ candy to the audience while the trashcano was being set up, to discuss the tiny explosions caused by release of pressurized CO2 gas bubbles.
- Teamed up with ASU’s Robotics group to film the explosions with a quadcopter drone fitted with a camera, and projected the footage onto a big screen in real-time .
- Filmed the action with the FLIR ONE thermal camera, a handheld iPhone attachment that detects infrared. We also compared this footage with the real deal FLIR camera from ASU’s Mars Space Flight Facility.
Update: We created a Trashcano demonstration for the USGS Cascades Volcano Observatory Open Day in May 2015, which was covered by the Columbian in Illustrating the Science of an Active Volcano
Here are some images and videos from ASU’s Earth and Space Exploration Day.
FLIR thermal camera footage by Michael Veto from ASU’s Mars Space Flight Facility, slowed to 0.25x actual speed
Drone footage by Ben Stinnett of ASU Engineering. Notice how the water-filled balloons (red) are not as widely dispersed as the air-filled balloons (gold) .
Handheld FLIR ONE iPhone attachment thermal camera footage taken by Sarah Cichy, slowed to 0.25x actual speed