On the other side of the globe, in a whirl of commingling currents, the Great Pacific Garbage Patch is the repository for the ocean’s debris. Here in Washington, in a smaller ocean, explorers are on the verge of discovering a similar phenomenon: the National Building Museum’s Great iPhone Vortex.

Chances are, somebody in this picture lost an iPhone. (Alex Wong/Getty Images)

It has happened nearly 100 times this summer: A visitor goes to the museum’s exhibition “The Beach,” an all-white seascape of plastic balls by Snarkitecture, and belly-flops into the “water.” Meanwhile, the person’s phone belly-flops out of his or her pocket and sinks beneath the nearly 1 million balls. And disappears.

“It’s like the Bermuda Triangle,” said Kristen Sheldon, ordinarily the museum’s volunteer and intern coordinator, but since shortly after the July 4 opening of the beach, the self-proclaimed “queen of the lost and found.”

“What’s causing that? Is there a current? I don’t understand,” Sheldon said. “I think it’s probably a physics paper for somebody — the physics of a giant ball pit.”

[Update: The National Building Museum found $433.24 in loose change at the bottom of ‘The Beach’]

Where have all the iPhones gone? Some resurface an hour, a day, a week later. Some, tracked by phone-finding apps, inexplicably migrate from one end of the ocean to the other. Some, despite hours of desperate digging, have never been seen again. Sheldon thinks that when the exhibit is torn down after Monday, Sept. 7, she’ll find the phones and reading glasses and flip-flops and Fitbits and toys that have slipped through the cracks. And when she does, she’ll go through her binder of lost-and-found claims — far exceeding 700 entries at this point — to reunite each item with its owner. With any luck.

One couple was very, very lucky. Recently engaged, they took a dip at “The Beach.” When they came back to shore, they realized that the woman’s brand-new engagement ring, feeling so awkward and unfamiliar on her finger, had slipped off.

“She was just heartbroken. We felt terrible, it was the first major piece of jewelry that was lost,” Sheldon said. “They really tried to look. Visitors were helping them, staff was helping them.”

How many stuffed toys and sunglasses have sunk to the bottom of Davy Jones’s ball pit? Time will tell. (Alex Wong/Getty Images)

But digging through a ball pit can be a Sisyphean task: The deeper a dent you make, the more it sets surrounding balls into motion, rolling them back into the hole. The constant movement of kids and adults means that items can shift far from where they were last seen — and sometimes surface unexpectedly. That’s what happened with the engagement ring a few weeks later, when a group of visitors digging for a lost phone found the ring instead.

“I was giving high-fives to visitors. It was a big deal,” Sheldon said. “Of course, now there are probably eight wedding rings, bands and engagement rings in there.”

The Building Museum knew that there would be lost items resulting from their blockbuster summer exhibit. But they didn’t quite anticipate this: a record-breaking 160,000 visitors and what Sheldon estimates to be nearly 1,000 items either reported lost or turned in and unclaimed.

“Within the first couple of days, it was very clear what was going on,” Sheldon said. “There were going to be many items lost at sea, and we had to do our best to return them to their owners. We started out with a nice little one-inch binder, and then it was two inches, and then it was 3 1/2 , and now it’s two binders and a notebook just to contain all the paperwork.”

Phones are one of the most commonly lost items, but single shoes are a close second. (Some guests apparently manage to hobble home half-barefoot, while others buy flip-flops in the museum gift shop.) Sunglasses often don’t survive the swim: Volunteers find smashed-up bits of them washed ashore. Unlabeled Fitbits and fitness trackers can be sent back to their manufacturers for identification. There are six selfie sticks of varying colors, a one-gallon plastic bag filled entirely with lens caps, and a few items that make Sheldon nervous, such as two pagers that she presumes belong to doctors and an inhaler. She has found and reunited wallets with their owners — one even brought her flowers in gratitude — but sometimes, there’s nothing to be done.

“I lost $43 in cash and told all the kids it was theirs if they found it,” tweeted @tichugrrl after a recent visit.

“You hear stories where kids magically pull money out of their pocket in the gift shop, and when the parents ask, ‘Where did it come from?’ ” they say in “The Beach,” Sheldon said. The staff hasn’t yet started an over/under bet on the dollar amount that will be recovered from the bottom, but the loose change and bills will be counted as museum donations.

Fitbits and flash drives are frequently lost. (National Building Museum)

This engagement ring was happily retrieved by its owner. Wedding bands and rings are also commonly lost items. (National Building Museum)

The final destination of other leftover items is still TBD. After a long enough interval, unclaimed clothes and sunglasses will be donated to a shelter or to Goodwill. Sheldon is hoping that the iPhones can be given to well-vetted charities that wipe them clean and donate them to victims of domestic abuse. The unpaired shoes are probably a lost cause. The lens caps may be, too. “I almost want to call a camera shop and ask, ‘Can you use 40 Canon lens caps of different sizes?’ ”

Sheldon has learned a few things about Washington and its visitors through handling their lost items and helping them through crises small and large. People are bad at describing their belongings. (“Even wedding bands. They’re like, ‘I think it has inscriptions on it.’ What do you mean you think it has inscriptions?”) Men and women are equally likely to lose things. Washingtonians are really into their Sperry boat shoes. People are, for the most part, honest.

And: Never assume that even a seemingly insignificant item is worthless. Take the faded bandana that Sheldon assumed wouldn’t be worth the Metro fare to retrieve. But when she contacted the owner, the woman thanked her for taking her inquiry seriously, and told Sheldon that she had been wearing that bandana for 20 years.

It reminded Sheldon that “there’s no such thing” as an item with no value.

“Which, to be honest, speaking as a museum person, we know that,” she said. “We’re all about objects.”