A Criteria: Must be the brightest color and the lightest in the class. Constraints: Warms 100 mL of water by at least 2°C in 15 minutes; No electricity.
B Criteria: Warms 100 mL of water by at least 2°C in 15 minutes; Looks neat and impressive. Constraints: Use a pizza box, foil, and plastic wrap; No electricity; Build time is 45 minutes.
C Criteria: Warms 100 mL of water by at least 2°C in 15 minutes; Water cup stays upright. Constraints: Use a pizza box, foil, and plastic wrap; No electricity; Build time is 45 minutes.
D Criteria: Warms 100 mL of water by at least 2°C in 15 minutes; Water cup stays upright. Constraints: Use a pizza box, foil, and plastic wrap; No electricity; Must cost $0 and be built in 2 minutes.
