The 11-minute YouTube video starts out with former NASA engineer Mark Rober enlisting a handful of kids to collect two water bottles full of the grossest, dirtiest water they can find. At first, each sample looks identically disgusting. Then Rober pours some white powder into one of the bottles, and asks his young lab assistants to shake it.
After several minutes, the murkiness is gone, cuing the sort of must-share moment that Rober has become internet famous for. He inserts a straw, sips, and swallows loudly. “Ah, that’s some high quality H20 right there,” he says to the wide-eyed kids.
Since October 2011, Mark Rober has starred on the eponymous Mark Rober YouTube channel, which releases one entertaining science- and tech-related video per month and has over 6.1 million subscribers. As an engineer, he likes to identify everyday problems and then fix them, typically through some mechanical hack or built contraption. They often go viral. (see: “Package Thief vs. Glitter Bomb Trap” and “Skin a Watermelon Party Trick“).
The water-purifying video–called “Drinking Nasty Swamp Water (to save the world)“–is a little less whimsical, since it’s sponsored by billionaire philanthropist Bill Gates, who also makes a guest appearance as the video goes on. They use the magical powder, which is manufactured by Proctor & Gamble and donated to people around the world who lack clean drinking water, to make a case that philanthropy matters.
Rober released the video to help promote Bill and Melinda Gates’s annual letter about that state of the world, which the couple traditionally uses to benchmark social progress, share their foundation’s work, and outline their optimistic vision of the future. Over the last two weeks, nearly 6 million people have now watched the episode, making it one of Rober’s fastest-rising hits.
This was the third annual video Rober made to support the letter. He also investigated the genius of a cheap paper centrifuge to diagnose malaria in areas without electricity, and defended the modern value of NASA because its satellite arrays help monitor and predict sweeping global changes. It’s a different kind of media collaboration for Gates, who is famous for staging his own carefully managed events. Rober doesn’t give Gates any editorial control of the videos, but they must loosely tie into a general theme in that year’s letter, which is referenced at the end of the show.
As Rober explains in the latest video, Proctor & Gamble invented the powder while researching better laundry methods. (The key ingredients are a coagulant, flocculants, and chlorine, which trap dirt, sink it, and neutralize harmful bacteria and parasites, respectively.) Given that nearly 1 billion people around the world don’t have access to clean drinking water, they decided to start giving it away to change that.
But efforts like this all cost money, and not everyone in the world agrees that spending it overseas is good thing. So this year Rober decided to explore if there’s a more selfish rationale for doing good. As he put it to his viewers: “Is there a case to be made beyond altruism where it’s in the best interest of the rich countries to help out the poor countries?”
That’s in line with what Bill and Melinda have called “the nationalist case” for saving the world. “The reason that countries like the U.S. invest in foreign aid is that it increases stability abroad and security at home,” they wrote in their most recent letter. Gates didn’t appear in Rober’s first two videos, but this year seemed open to it. Rober liked the idea–but only if he could also shake the format up. “If it’s him and me sitting in a chair by a fireplace talking, people don’t want to see that,” he says. “It doesn’t matter who you are talking to. That’s not interesting. That’s not my channel. That’s not my voice.”
His solution was to meet Gates in his Seattle kitchen for a candid talk. When he got there, Rober took a minute to cook up some microwave pizza rolls. He’d told Gates this would happen ahead of time. To his credit, Gates bit. (“It’s really hot, actually… not bad,” Gates says politely.) As a second course, Rober pranked him with a carryout bag of burgers from Dick’s, one of Gates’s favorite local spots. Instead, it contained some dirty water samples, so he could see the powder in action. (“I’d rather eat these than that so far,” Gates said, glancing back to the pizza rolls.)
The scene highlights how Gates is rich, smart but also approachable. “He happens to be a rich dude. But he’s also just a normal dude who realizes he can do good stuff with his money. And you really get that impression by speaking with him,” Rober says.
The two riff fairly casually about why helping others really matters to your own self-interest. As economically unstable places improve, for instance, the potential for radicalization and people fleeing decreases. As the health systems improve, it allows more people to contribute to the global economy, and increases the chance of spotting and stopping global pandemics like Ebola.
Rober’s favorite point is about the power of human capital. As the video makes clear, Albert Einstein may be considered one of the smartest people ever, but that’s in part because he had time to sit and think. When people previously relegated to survival-mode can tap their brainpower for other things, it increases the chances of them generating their own creative ideas and inventions.
For Rober, the fact that the video continues to spread shows its power. “I think it shows that if you can do it right, there’s an appetite for optimism in the world, especially as it relates to science and engineering… You can make the good stories just as compelling.”