Mason McCarty, 14, tried to stay calm.McCarty had just finished second in the middle school racing portion of Saturday’s Clark Public Utilities’ Solar Car Challenge at Hudson’s Bay High School in Vancouver. McCarty recorded that placing along with his friend Aran O’Day, 14, who attends eighth grade with him at Odyssey Middle School in Camas.“I’m still shaking from the adrenaline,” McCarty said, looking down at his hands minutes after finishing racing for the day.“It was really fun competing,” O’Day said.McCarty and O’Day made up one of more than 175 teams from Clark County elementary, middle and high schools that competed in the competition. Students placed in racing competitions, as well as other categories such as best design. The challenge was organized to teach kids about STEM in a fun way. McCarty and O’Day said they enjoyed using trial and error to build their solar battery-hybrid car.“I saw everybody having fun, even if they didn’t win,” McCarty said.McCarty and O’Day said they think their car fared so well because they tested three gear ratios before deciding which one worked best. They also cycled through solar panels before choosing the most aerodynamic option.Heather Allmain, communications services manager for Clark Public Utilities, said Saturday’s race was a culmination of a couple of months of work from the students. About 700 teams received solar car kits in January courtesy of the utility’s Green Lights program and partnerships with WaferTech and Columbia Credit Union.On Saturday, the solar cars had to meet a checklist of specifications before the cars could qualify for the race. The students did poster presentations on their cars, and technical industry professionals interviewed them about their designs. The solar challenge is like combining a science fair with a pinewood derby.