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    Science

    Welcome to Khan Academy's free science resources. Watch videos, read articles, and expand your knowledge in any science topic.

    Start your biology adventure
    Main content

    Biology

    Life is beautiful! From atoms to cells, from genes to proteins, from populations to ecosystems, biology is the study of the fascinating and intricate systems that make life possible. Dive in to learn more about the many branches of biology and why they are exciting and important. Covers topics seen in a high school or first-year college biology course.

    Physics

    Learn about the basic principles that govern the physical world around us. Solid understanding of algebra and a basic understanding of trigonometry necessary.

    Chemistry

    Did you know that everything is made out of chemicals? Chemistry is the study of matter: its composition, properties, and reactivity. This material roughly covers a first-year high school or college course, and a good understanding of algebra is helpful.

    Organic chemistry

    Sal and Jay cover topics covered in college organic chemistry course. Basic understanding of basic high school or college chemistry assumed (although there is some review).

    Cosmology and astronomy

    Videos attempting to grasp a little bit about our Universe (many of the topics associated with "Big History")

    Health and medicine

    The medical world can be a confusing place. Patients and their families might feel overwhelmed by the large vocabularies and complicated explanations they get from their health care providers. Students entering health care also struggle to grasp the complexity of health sciences, and are forced to memorize huge amounts of information. We hope to make understanding the medical world a bit easier. Look around! These videos do not provide medical advice and are for informational purposes only. The videos are not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of a qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay seeking it because of something you have read or seen in any Khan Academy video.

    Electrical engineering

    Electrical engineering is the study of electrical energy and information. These topics are part of the electrical engineering major taught in the first and second year of college. We cover electricity, circuit theory, and introductory electronics. For the budding electrical engineer: We have topics showing how to build your own robot, plus videos where we disassemble household items to see what is inside.