As an emergency physician at Western Health, in Melbourne, Australia, Dr. Andy Tagg says he meets a lot of anxious parents whose children have swallowed Lego pieces. Much like Andy so many years ago, the vast majority of kids simply pass the object through their stool within a day or so. But Andy and five other pediatricians wondered, is there a way to give parents extra reassurance ... through science? So the doctors devised an experiment. "Each of them swallowed a Lego head," says science journalist Sabrina Imbler, who wrote about the experiment for The Defector. "They wanted to basically see how long it took to swallow and excrete a plastic toy." On today's episode, Sabrina joins Scientist in Residence Regina G. Barber to chart the journey of six lego heads, and what came out on the other side. Learn about Sabrina Imbler's recent book, How Far the Light Reaches, at their website.Editor's note: This episode contains frequent and mildly graphic mentions of poop. It may cause giggles in children, and certain adults.