Several years ago a children’s hospital ran a simple experiment. They gave each child a small yellow rubber ball—nothing fancy, nothing expensive. Then they turned off the lights in the playroom and switched on a blacklight. Suddenly, the entire room erupted with little glowing yellow dots bouncing, flying, and rolling in every direction. The kids were laughing, shouting, chasing their little glowing treasures. For a moment, the IV poles, the bandages, and the pain were forgotten. Nurses said it was the loudest laughter they had heard in weeks.
