Learn biology using videos, articles, and NGSS-aligned practice. Review the fundamentals of cell biology, organism growth and reproduction, photosynthesis, cellular respiration, ecology, genetics, evolution, and natural selection.
Learn Earth and space science using videos, articles, and NGSS-aligned practice. Review the fundamentals of space systems, weather and climate, Earth's history and systems, and human impacts.
Learn biology using videos, articles, and NGSS-aligned practice. Review the fundamentals of cell biology, physiology, genetics, biochemistry, natural selection, and ecology.
Learn high school chemistry using videos, articles, and NGSS-aligned practice. Explore the fundamentals of atomic structure, chemical bonding, chemical reactions, thermochemistry, solutions, acids and bases, and nuclear chemistry.
This algebra-based course covers the main topics in high school introductory and honors physics, including motion, force, work, energy, momentum, collisions, torque, waves, sound, static electricity, and circuits.
Learn High School Physics using videos, articles, and NGSS-aligned practice. Review the fundamentals of kinematics, forces, fields, energy in systems, electromagnetic radiation, and communication technology.
Learn AP Biology using videos, articles, and AP-aligned multiple choice question practice. Review the fundamentals of biochemistry, cell biology, genetics, evolution, and ecology, and develop scientific thinking skills as you explore the study of life.
Learn AP Chemistry using videos, articles, and AP-aligned practice. Review the fundamentals of atomic structure, intermolecular forces and bonding, chemical reactions, kinetics, thermodynamics, and equilibrium.
Learn AP Environmental Science using videos, and AP-aligned practice. Review the fundamentals of ecosystems, biodiversity, populations, earth systems and resources, land and water use, energy resources and consumption, pollution, and global change.
An algebra-based, introductory college-level physics course that explores topics such as fluid statics and dynamics; thermodynamics with kinetic theory; PV diagrams and probability; electrostatics; electrical circuits with capacitors; magnetic fields; electromagnetism; physical and geometric optics; and a whole lot more.
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).
The medical world can be a confusing place. Patients, their families, and even students entering health fields might feel overwhelmed by the large vocabularies and complicated explanations. 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.
It's a great, big universe out there. In this section of Khan Academy, you'll learn about the brain-bending vastness of time and space. We go from plate tectonics here on Earth to entire galaxies and beyond.
Learn about electricity, circuit theory, and introductory electronics. We also have sections that let you get down and dirty with household items, from building your own robot to videos where we disassemble household items to see what's inside.
Welcome to the Biology library! Biology is the study of life. Here, you can browse videos, articles, and exercises by topic. We keep the library up-to-date, so you may find new or improved content here over time.