The Story Behind the Reservoir Covered With 96 Million Balls

Why is a reservoir in Los Angeles covered with 96 million floating balls? To keep the sunlight from affecting the water. But lakes and reservoirs exist all over the world with sun shining on them. Veritasium host Derek Muller went there to find out what the story is. While the balls were an idea to solve a chemistry problem, they turned out to have other benefits, too. (via Laughing Squid)