Additional Study Information: How does the light we experience in day-to-day life affect our body clock? Interested in joining a new project to help scientists at Columbia University understand how light pollution and light-at-night affects our body clock? You or your child may be eligible to participate. The study involves wearing a small light sensor on a lanyard and a temperature sensor in a wristband for one week in the summer, fall, winter and spring. You will also be asked to fill out a daily questionnaire during those weeks. $30/week compensation or $120 in total for participation.