Hypnotic Slow-Motion Video Shows How Scientists Made Lava Explode in a Lab

Anyone who’s splashed a little water into hot oil knows that the results can be disastrous. But when water and magma combine, it’s even wilder. The violent reaction between magma and water happens all the time when volcanoes erupt into the ocean, but the phenomenon is nearly impossible for scientists to get close enough to study, so the next best option is to recreate the phenomenon in a big bucket. And this is what researchers at the University of Buffalo did to help them start studying this often-seen but poorly understood phenomenon. As shown in the video above, the instant the hammer falls and injects water into a mass of magma, it creates a huge, explosive bubble of molten rock that splashes everywhere, even when you’re just mixing them in a bucket. It’s just a taste of what happens when actual volcanoes erupt into the sea.

In a paper published Monday in the Journal of Geophysical Research: Solid Earth, a team of scientists led by Ingo Sonder, Ph.D., a research scientist in the Center for Geohazards Studies at the University of Buffalo, described why they mixed water into magma — and no, they didn’t just do it to see what would happen, though that was a big part of it. In a series of experiments, they injected various amounts of water into different-sized containers of molten rock to explore the laws behind the explosive reactions that occur when the two substances combine.

“If you think about a volcanic eruption, there are powerful forces at work, and it’s not a gentle thing,” Sonder said on Monday. “Our experiments are looking at the basic physics of what happens when water gets trapped inside molten rock.”

And to do this, Sonder and his team captured lots of videos of their Rube Goldberg-inspired water-injection rig, which uses a remote-operated sledgehammer to trigger a water jet that pricks the magma from below. As the water boils instantly, it forms a bubble of magma that bursts instantly.

If the explosive effect of the water injection in the video up top made it hard to see what happened, check out this one:

Or this one, which was shot in black-and-white, giving a much better sense of how the initial explosion gave way to a violent simmer as the water boiled off:

The team’s method differs from past research on magma both in the volume they used and in the substance itself. Previous research, the authors write, has used either a thermite-based magma substitute in a large volume or actual remelted volcanic rock in a small container. In the latest experiments, the researchers used both: a large volume of actual remelted magma. In this way, they hope their experiment is a lot more realistic than past efforts.

What they found was that when a column of magma is as little as one foot high, contacting water produces a significant eruption. This may not come as much of a surprise, but nonetheless, it helps other scientists get a better idea of the physics involved in water-magma interactions. Plus, it looks almost as cool as when Mount Kilauea’s latest eruption gave birth to an explosive hale of green glass.