Keep going! Check out the next lesson and practice what you’re learning:

Passive solar energy systems absorb heat directly from the sun without the use of mechanical and electric equipment, and energy cannot be collected or stored. Active solar energy systems use solar energy to heat a liquid through mechanical and electric equipment to collect and store the energy captured from the sun. Photovoltaic solar cells capture light energy from the sun and transform it directly into electrical energy. Their use is limited by the availability of sunlight.

Khan Academy is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We offer quizzes, questions, instructional videos, and articles on a range of academic subjects, including math, biology, chemistry, physics, history, economics, finance, grammar, preschool learning, and more. We provide teachers with tools and data so they can help their students develop the skills, habits, and mindsets for success in school and beyond. Khan Academy has been translated into dozens of languages, and 15 million people around the globe learn on Khan Academy every month. As a 501(c)(3) nonprofit organization, we would love your help!

Donate or volunteer today! Donate here:

Volunteer here:


“Greenroof” by pnwra [Public domain], via Wikimedia Commons:

“Santa Fe adobe” by Carol m [Public domain], via Wikimedia Commons:

“Home awnings” by Conarty [Public domain], via Wikimedia Commons:

“Thermal solar collector” by Norbert Nagel [Public domain], via Wikimedia Commons:

“Ivanpah” by Craig Butz [Public domain], via Wikimedia Commons:

“Heliostats” by Alexchris [Public domain], via Wikimedia Commons:

“Mersin CSP field” by Kohsman [Public domain], via Wikimedia Commons:

“Solar calculator” by Rfassbind [Public domain], via Wikimedia Commons:

Email This Post Email This Post