The National Science Bowl is an annual science competition created by the Department of Energy in 1991 to encourage American high school students to excel in math and science and to pursue careers in these fields. The Department of Energy supports math and science education to help provide a technically trained and diverse workforce for the agency and the nation.
The competition consists of questions on scientific topics in astronomy, biology, chemistry, mathematics, physics, earth science and general science (this topic includes questions on science history and computer science).
Competition consists of a round robin competition, followed by a double elimination final. during the round robin, teams are awarded two points for a win, one point for a tie, and zero for a loss. The top two teams from each flight continue to the double elimination round.
Teams are made up of five memebers, of which four compete during any portion of the competition, and the fifth is an alternate. Any team member may be the alternate during a round, and typicaly all team members participate during some part of the competition.
There are two types of questions, toss-up and bonus, which may be asked as multiple choice or short answer questions. Players work individually on toss-up questions, buzzing in if they have an answer. Their team is awarded four points for getting a toss-up question, and then is given the opportunity to gain ten more points by answering a bonus question. Team members are allowed to confer on bonus questions, and are given more time to answer than for toss-ups.
Regional conpetitions are held between January and March throughout the country, with a different set of questions for each region. The winnning team from each region goes on to the national competition, which is held in early May. There are 64 regions, 62 which cover all areas of the country, and two others to represent Native American students and the National Organization of Black Chemists and Chemical Engineers, making for nice groupings of eight teams in round robin competition.
Sources:
http://www.scied.science.doe.gov/nsb/default.htm
Personal experience