Ever since the light bulb's invention 150 years ago, artificial light has illuminated homes, streets, and skies -- but with some unintended consequences. Learn about the major types of light pollution, their impact on human health, and how the worldwide glow from artificial light may continue to grow.
Beakman uses ping pong balls to simulate electrons. He rolls them down a pipe that gets narrower so they pile up (resistance). In a light bulb, the resistance causes the coil to heat up and make light.