Michigan State professor and urological surgeon David Wartinger noticed that some of his patients tended to come home from vacation with fewer kidney stones, mainly because they told him about passing kidney stones while visiting the Disney theme parks in Orlando. One man passed three kidney stones, one every time he rode the Big Thunder Mountain Railroad. Wartinger decided to investigate by going to Florida himself.
First, Wartinger used a 3-D printer to create a clear silicone model of that three-time-stone patient’s kidney. He then filled the kidney with stones and urine. (Not real urine, I assumed, as I know the park already has plenty.) Then he and colleague Marc Mitchell bought two tickets and flew to Orlando.
Of course, the researchers had to get permission from Disney World before bringing the model kidney onto the rides. “It was a little bit of luck,” Wartinger recalls. “We went to guest services, and we didn't want them to wonder what was going on—two adult men riding the same ride again and again, carrying a backpack. We told them what our intent was, and it turned out that the manager that day was a guy who recently had a kidney stone. He called the ride manager and said, do whatever you can to help these guys, they're trying to help people with kidney stones.”
Amazingly, the fake kidney passed the stones in the real urine, in 16.67 percent of the rides in the front of the coaster and 63.89 percent of rides in the back of the coaster.
“No, it was urine. It was mine.”