Off the Grid
A unit on solar energy begins with pupils researching vocabulary terms related to electric currents. They then use a multimeter to measure the voltage and current for a solar module before calculating power and efficiency. Fun, hands-on activities have learners calculating the efficiency of cell phone chargers by measuring the power in and power out. Other activities have them read and use circuit diagrams, examine buck and boost converters, and learn how to adjust the output voltage to match the needs of a USB charger. The investigation of the efficiency of a USB charger—after watching instructors perform a demonstration that uses a camping stove to generate electricity to charge a phone, class members use data from the experiment to calculate the efficiency of the stove. Finally, working in groups, scholars design a solar phone charger by applying concepts from the unit. They use solar modules and buck and boost converters in their creations, which must charge a phone after receiving four hours of sun.