Random International, Rain Room, 2012. Photo courtesy of the artist. 

What surprised artist Hannes Koch most about Rain Room (2012), an installation which he co-created that consists of a field of falling water that stops when it detects a presence, was not how well it was received. It broke attendance records at the Barbican in London earlier this year. Instead, Koch was impressed by the way the work serves as a kind of memory chamber for so many people, himself included.

"I remember massive midnight rainstorms in Italy, where I used to vacation with my family as a child," Koch said. "Afterwards, the streets would become like rivers, and my mom would make bouillon to keep us warm."

Rain Room
, on view at MoMA (through July 28) as part of MoMA PS1's multi-exhibition Expo 1 initiative (through Sept. 2), was conceived by the collective Random International, which Koch founded in 2005 with Stuart Wood and Florian Ortkrass, fellow graduates of London's Brunel University. Known for creating high-tech immersive installations that respond to human presence, they first conceived of Rain Room as a way to explore what it would feel like for a human to be totally subsumed in a physical environment.

Expo 1 explores the way ecological changes have contributed to 21st-century economic and political instability, and positions art as having a responsibility to raise awareness. The initiative, put into motion by MoMA chief curator at large Klaus Biesenbach after Hurricane Sandy, includes a school run by online magazine Triple Canopy and a geodesic dome for exhibitions and events on Rockaway Beach in Queens, where Biesenbach has a home. The Rain Room doesn't make overt statements—rather, it lets visitors play God by allowing their very presence to stop the flow of an element usually controlled by nature.

The work is installed in a 5,000-square-foot tent in an empty lot to the west of the MoMA building. Inside, the room is black except for a gigantic white light at the far end, which illuminates the downpour that falls at a rate of 260 gallons per minute.

As a group watched from the sidelines during a press preview Friday, a few visitors walked tentatively into the downpour, only to find that wherever they stepped, the rain stopped entirely. The effect is achieved by a sophisticated tracking system made of cameras on either side that communicate with the water valves. When they detect a living presence—Koch said that dogs can also stay dry in the downpour—they cause the valves to close at a very high speed.

The effect is magical. You reach out your hand quickly, and the water withdraws. You try to fool the installation by making random movements, but it stays one step ahead of you. In the room's humidity—the atmosphere is as balmy as a zoo's reptile house—one begins to want to touch the water.

At the Barbican, the installation attracted 12-hour lines, with people camping out in the final days, according to Koch. The installation can only hold a dozen people at a time, otherwise  the system gets overloaded and the rain stops falling. It remains to be seen if people will wait as long at MoMA. One suspects that they will, since the childlike wonder evoked by the experience is hard to find in daily life.