Online courses directory (381)

Everything in the universe can be measured. Under Pressure. Earth's Tilt 1: The Reason for the Seasons. Earth's Tilt 2: Land of the Midnight Sun. 2D Equilibrium -- Balancing Games. Under Pressure. Earth's Tilt 1: The Reason for the Seasons. Earth's Tilt 2: Land of the Midnight Sun. 2D Equilibrium -- Balancing Games.

Start your own robotics project with Spout, Spider, and Bit-zee!. 3rd graders build robots at Santa Rita Elementary School. See inside Spout's motors and switches. Spout 1. Spout 2. Spout 3. Spout 4. Spout 5. Spout 6. Spout 7. Spout 8. Spout 9. Spout 10. Spout 11. 6th graders learn to build a Spider robot. Parts list for Spider. 1 Spider parts and tools. 2 Hacking Spider's click n' stick. 3 Creating the battery and motor mounts for Spider. 4 Attach Spider's click n' stick base to the batteries and thread his wires. 5 Attach Spider's motor controller and wire his motors. 6 Connect Spider's power switch and run the power wires to the motor controller. 7 Attach and adjust the Spider's bezel. 8 Attach Spider's wheels. 9 Make the connnectors for Spider's Arduino Nano. 10 Spider Connect the power and signal wires from the motor controller to the Arduino. 11 Attach Spider's LED eyes. 12 Connect Spider's stablizer bar. 13 Spider's Romance. 14 Teaching Spider to dance. 15 Ben Eater's Spider Bot. 1. Bit-zee. 2. Bit-zee (long version). 3. Bit-zee Bot Introduction. 4. Bit-zee planning and propulsion. 5. Bit-zee's bits. 6. Bit-zee's chassis/frame. 7. Bit-zee's wheel mounts and fenders. 8. Bit-zee's component mounting holes. 9. Bit-zee's batteries. 10. Improving the battery wires. 11. Connecting Bit-zee's power wires and on-off switch. 12. Bit-zee's motors. 13. Why does Bit-zee need a motor controller?. 14. Bit-zee's motor controller. 15. Attaching and wiring Bit-zee's motor controller. 16. Attaching Bit-zee's Arduino. 17. How to hotwire a digital camera. 18. Attaching Bit-zee's digital camera. 19. Bit zee's 5 Volt power distribution board. 20. Hacking and attaching a digital recorder/player to Bit-zee. 21. Making a power connector for the Arduino. 22. Attaching Bit-zee's prototype board. 23. Connecting the motor controller to the Arduino. 24. Connecting Bit-zee's camera to the Arduino. 25. Bit-zee's bumper switches. 26. Bit-zee's eyes. 27. Bit-zee's IR sensor. 28. Bit-zee's shell. 29. Camera wiring update. 30. Load the Code for It-zee and Bit-zee. 1 Spout Introduction. 2 Attach Spout's lever switches and motors. 3 Attach Spout's wires and connectors. 4 Attach Spout's sliding switches and resistors. 5 Connect Spout's antenna. 6 Attach Spout's LED eyes. See inside Spout's motors and switches. 3rd graders build robots at Santa Rita Elementary School. See inside Spout's motors and switches. Spout 1. Spout 2. Spout 3. Spout 4. Spout 5. Spout 6. Spout 7. Spout 8. Spout 9. Spout 10. Spout 11. 6th graders learn to build a Spider robot. Parts list for Spider. 1 Spider parts and tools. 2 Hacking Spider's click n' stick. 3 Creating the battery and motor mounts for Spider. 4 Attach Spider's click n' stick base to the batteries and thread his wires. 5 Attach Spider's motor controller and wire his motors. 6 Connect Spider's power switch and run the power wires to the motor controller. 7 Attach and adjust the Spider's bezel. 8 Attach Spider's wheels. 9 Make the connnectors for Spider's Arduino Nano. 10 Spider Connect the power and signal wires from the motor controller to the Arduino. 11 Attach Spider's LED eyes. 12 Connect Spider's stablizer bar. 13 Spider's Romance. 14 Teaching Spider to dance. 15 Ben Eater's Spider Bot. 1. Bit-zee. 2. Bit-zee (long version). 3. Bit-zee Bot Introduction. 4. Bit-zee planning and propulsion. 5. Bit-zee's bits. 6. Bit-zee's chassis/frame. 7. Bit-zee's wheel mounts and fenders. 8. Bit-zee's component mounting holes. 9. Bit-zee's batteries. 10. Improving the battery wires. 11. Connecting Bit-zee's power wires and on-off switch. 12. Bit-zee's motors. 13. Why does Bit-zee need a motor controller?. 14. Bit-zee's motor controller. 15. Attaching and wiring Bit-zee's motor controller. 16. Attaching Bit-zee's Arduino. 17. How to hotwire a digital camera. 18. Attaching Bit-zee's digital camera. 19. Bit zee's 5 Volt power distribution board. 20. Hacking and attaching a digital recorder/player to Bit-zee. 21. Making a power connector for the Arduino. 22. Attaching Bit-zee's prototype board. 23. Connecting the motor controller to the Arduino. 24. Connecting Bit-zee's camera to the Arduino. 25. Bit-zee's bumper switches. 26. Bit-zee's eyes. 27. Bit-zee's IR sensor. 28. Bit-zee's shell. 29. Camera wiring update. 30. Load the Code for It-zee and Bit-zee. 1 Spout Introduction. 2 Attach Spout's lever switches and motors. 3 Attach Spout's wires and connectors. 4 Attach Spout's sliding switches and resistors. 5 Connect Spout's antenna. 6 Attach Spout's LED eyes. See inside Spout's motors and switches.

Rediscover the most important observations in history. Discovery of Magnetism. Compass: which way is north?. Floating Magnet. Compass Build (stroke direction). Compass Build (magnet orientation). Neutralize a Compass. Compass Interactions. Magnetising materials. What's Next?. Magnet near Compass. Tracing a Magnetic Field. Tracing a magnetic field. Discovery of Magnetic Fields. Magnet and iron filings. Magnetic field. 3D magnet with field. Magnetic Permeability. Increase Strength of Magnet. What's Next?. Are 2 magnets stronger than 1?. Measure the Earth!. Earth's Magnetic Field (how to measure). Force over Distance. Inverse Square Law (deflection method). Inverse Square Relationship. Inverse Square Law (Method of Oscillation). Zinc Copper cell (reduction-oxidation). How to Measure?. Battery Meter (Galvanometer). How Many Turns?. Electrolyte Test (pure water vs. vinegar). Reverse Electrodes (polarity). Electrolyte (strong acid test). Electrolyte (salt test). Electrode (distance test). Electrolyte (temperature test). Electrode (surface area test). Standard Cell. How much electrolyte does a single cell need?. What's Next?. Discovery of Electromagnetism. Experiment: Electromangetism. Electromagnetic Field (above vs. below). Electromagnetic Field (forward vs. reverse). Electromagnetic Field (loop). Right-Hand Rule. Battery Meter (Galvanometer). Series Load. Pencil Resistor. Variable Resistor (Pencil). Listen to Variable Resistance. What's Next?. Electromagnet (construction tip). Electromagnet (penny powered). Understanding Force. Spinning Compass. Build your own motor. What's Next. Discovery of Triboelectric effect. Pith Ball Electroscope. Foil Leaf Electroscope. What's Next?. Discovery of Magnetism. Compass: which way is north?. Floating Magnet. Compass Build (stroke direction). Compass Build (magnet orientation). Neutralize a Compass. Compass Interactions. Magnetising materials. What's Next?. Magnet near Compass. Tracing a Magnetic Field. Tracing a magnetic field. Discovery of Magnetic Fields. Magnet and iron filings. Magnetic field. 3D magnet with field. Magnetic Permeability. Increase Strength of Magnet. What's Next?. Are 2 magnets stronger than 1?. Measure the Earth!. Earth's Magnetic Field (how to measure). Force over Distance. Inverse Square Law (deflection method). Inverse Square Relationship. Inverse Square Law (Method of Oscillation). Zinc Copper cell (reduction-oxidation). How to Measure?. Battery Meter (Galvanometer). How Many Turns?. Electrolyte Test (pure water vs. vinegar). Reverse Electrodes (polarity). Electrolyte (strong acid test). Electrolyte (salt test). Electrode (distance test). Electrolyte (temperature test). Electrode (surface area test). Standard Cell. How much electrolyte does a single cell need?. What's Next?. Discovery of Electromagnetism. Experiment: Electromangetism. Electromagnetic Field (above vs. below). Electromagnetic Field (forward vs. reverse). Electromagnetic Field (loop). Right-Hand Rule. Battery Meter (Galvanometer). Series Load. Pencil Resistor. Variable Resistor (Pencil). Listen to Variable Resistance. What's Next?. Electromagnet (construction tip). Electromagnet (penny powered). Understanding Force. Spinning Compass. Build your own motor. What's Next. Discovery of Triboelectric effect. Pith Ball Electroscope. Foil Leaf Electroscope. What's Next?.

Ping pong ball launcher introduction. Build a ping pong ball launcher . Update and modify your ping pong ball launcher. Ping pong ball launcher introduction. Build a ping pong ball launcher . Update and modify your ping pong ball launcher.

Thermo Can. Thermo Can.

Sal working through the 53 problems from the practice test available at http://www.cde.ca.gov/ta/tg/hs/documents/mathpractest.pdf for the CAHSEE (California High School Exit Examination). Clearly useful if you're looking to take that exam. Probably still useful if you want to make sure you have a solid understanding of basic high school math. CAHSEE Practice: Problems 1-3. CAHSEE Practice: Problems 4-9. CAHSEE Practice: Problems 10-12. CAHSEE Practice: Problems 13-14. CAHSEE Practice: Problems 15-16. CAHSEE Practice: Problems 17-19. CAHSEE Practice: Problems 20-22. CAHSEE Practice: Problems 23-27. CAHSEE Practice: Problems 28-31. CAHSEE Practice: Problems 32-34. CAHSEE Practice: Problems 35-37. CAHSEE Practice: Problems 38-42. CAHSEE Practice: Problems 43-46. CAHSEE Practice: Problems 47-51. CAHSEE Practice: Problems 52-53. CAHSEE Practice: Problems 1-3. CAHSEE Practice: Problems 4-9. CAHSEE Practice: Problems 10-12. CAHSEE Practice: Problems 13-14. CAHSEE Practice: Problems 15-16. CAHSEE Practice: Problems 17-19. CAHSEE Practice: Problems 20-22. CAHSEE Practice: Problems 23-27. CAHSEE Practice: Problems 28-31. CAHSEE Practice: Problems 32-34. CAHSEE Practice: Problems 35-37. CAHSEE Practice: Problems 38-42. CAHSEE Practice: Problems 43-46. CAHSEE Practice: Problems 47-51. CAHSEE Practice: Problems 52-53.

Sal works through problems in the 11th edition of the official GMAC GMAT Review (ISBN Number: 0-9765709-0-4 published in 2005). You should take the practice tests on your own, grade them and then use these videos to understand the problems you didn't get or to review. Have fun!. GMAT Math: 1. GMAT Math: 2. GMAT Math: 3. GMAT Math: 4. GMAT Math: 5. GMAT: Math 6. GMAT: Math 7. GMAT: Math 8. GMAT: Math 9. GMAT: Math 10. GMAT: Math 11. GMAT: Math 12. GMAT: Math 13. GMAT: Math 14. GMAT: Math 15. GMAT: Math 16. GMAT: Math 17. GMAT: Math 18. GMAT: Math 19. GMAT Math 20. GMAT Math 21. GMAT Math 22. GMAT Math 23. GMAT Math 24. GMAT Math 25. GMAT Math 26. GMAT Math 27. GMAT Math 28. GMAT Math 29. GMAT Math 30. GMAT Math 31. GMAT Math 32. GMAT Math 33. GMAT Math 34. GMAT Math 35. GMAT Math 36. GMAT Math 37. GMAT Math 38. GMAT Math 39. GMAT Math 40. GMAT Math 41. GMAT Math 42. GMAT Math 43. GMAT Math 44. GMAT Math 45. GMAT Math 46. GMAT Math 47. GMAT Math 48. GMAT Math 49. GMAT Math 50. GMAT Math 51. GMAT Math 52. GMAT Math 53. GMAT Math 54. GMAT: Data Sufficiency 1. GMAT: Data Sufficiency 2. GMAT: Data Sufficiency 3. GMAT: Data Sufficiency 4. GMAT: Data Sufficiency 5. GMAT: Data Sufficiency 6. GMAT: Data Sufficiency 7. GMAT: Data Sufficiency 8. GMAT: Data Sufficiency 9. GMAT: Data Sufficiency 10. GMAT: Data Sufficiency 11. GMAT: Data Sufficiency 12. GMAT: Data Sufficiency 13. GMAT: Data Sufficiency 14. GMAT: Data Sufficiency 15. GMAT: Data Sufficiency 16. GMAT: Data Sufficiency 17. GMAT: Data Sufficiency 18. GMAT: Data Sufficiency 19. GMAT: Data Sufficiency 20. GMAT: Data Sufficiency 21. GMAT Data Sufficiency 21 (correction). GMAT: Data Sufficiency 22. GMAT: Data Sufficiency 23. GMAT: Data Sufficiency 24. GMAT: Data Sufficiency 25. GMAT: Data Sufficiency 26. GMAT: Data Sufficiency 27. GMAT: Data Sufficiency 28. GMAT: Data Sufficiency 29. GMAT: Data Sufficiency 30. GMAT: Data Sufficiency 31. GMAT: Data Sufficiency 32. GMAT: Data Sufficiency 33. GMAT: Data Sufficiency 34. GMAT: Data Sufficiency 35. GMAT: Data Sufficiency 36. GMAT: Data Sufficiency 37. GMAT: Data Sufficiency 38. GMAT: Data Sufficiency 39. GMAT Data Sufficiency 40. GMAT Data Sufficiency 41. GMAT Math: 1. GMAT Math: 2. GMAT Math: 3. GMAT Math: 4. GMAT Math: 5. GMAT: Math 6. GMAT: Math 7. GMAT: Math 8. GMAT: Math 9. GMAT: Math 10. GMAT: Math 11. GMAT: Math 12. GMAT: Math 13. GMAT: Math 14. GMAT: Math 15. GMAT: Math 16. GMAT: Math 17. GMAT: Math 18. GMAT: Math 19. GMAT Math 20. GMAT Math 21. GMAT Math 22. GMAT Math 23. GMAT Math 24. GMAT Math 25. GMAT Math 26. GMAT Math 27. GMAT Math 28. GMAT Math 29. GMAT Math 30. GMAT Math 31. GMAT Math 32. GMAT Math 33. GMAT Math 34. GMAT Math 35. GMAT Math 36. GMAT Math 37. GMAT Math 38. GMAT Math 39. GMAT Math 40. GMAT Math 41. GMAT Math 42. GMAT Math 43. GMAT Math 44. GMAT Math 45. GMAT Math 46. GMAT Math 47. GMAT Math 48. GMAT Math 49. GMAT Math 50. GMAT Math 51. GMAT Math 52. GMAT Math 53. GMAT Math 54. GMAT: Data Sufficiency 1. GMAT: Data Sufficiency 2. GMAT: Data Sufficiency 3. GMAT: Data Sufficiency 4. GMAT: Data Sufficiency 5. GMAT: Data Sufficiency 6. GMAT: Data Sufficiency 7. GMAT: Data Sufficiency 8. GMAT: Data Sufficiency 9. GMAT: Data Sufficiency 10. GMAT: Data Sufficiency 11. GMAT: Data Sufficiency 12. GMAT: Data Sufficiency 13. GMAT: Data Sufficiency 14. GMAT: Data Sufficiency 15. GMAT: Data Sufficiency 16. GMAT: Data Sufficiency 17. GMAT: Data Sufficiency 18. GMAT: Data Sufficiency 19. GMAT: Data Sufficiency 20. GMAT: Data Sufficiency 21. GMAT Data Sufficiency 21 (correction). GMAT: Data Sufficiency 22. GMAT: Data Sufficiency 23. GMAT: Data Sufficiency 24. GMAT: Data Sufficiency 25. GMAT: Data Sufficiency 26. GMAT: Data Sufficiency 27. GMAT: Data Sufficiency 28. GMAT: Data Sufficiency 29. GMAT: Data Sufficiency 30. GMAT: Data Sufficiency 31. GMAT: Data Sufficiency 32. GMAT: Data Sufficiency 33. GMAT: Data Sufficiency 34. GMAT: Data Sufficiency 35. GMAT: Data Sufficiency 36. GMAT: Data Sufficiency 37. GMAT: Data Sufficiency 38. GMAT: Data Sufficiency 39. GMAT Data Sufficiency 40. GMAT Data Sufficiency 41.

SAT prep: test 1 section3 part 1. SAT Prep: Test 1 Section 3 Part 2. SAT Prep: Test 1 Section 3 Part 3. SAT Prep: Test 1 Section 3 Part 4. SAT Prep: Test 1 Section 3 Part 5. SAT Prep: Test 1 Section 3 Part 6. SAT Prep: Test 1 Section 3 Part 7. SAT Prep: Test 1 Section 3 Part 8. SAT Prep: Test 1 Section 6 Part 1. SAT Prep: Test 1 Section 6 Part 2. SAT Prep: Test 1 Section 6 Part 3. SAT Prep: Test 1 Section 6 Part 4. SAT Prep: Test 1 Section 6 Part 5. SAT Prep: Test 1 Section 6 Part 6. SAT Prep: Test 1 Section 9 Part 1. SAT Prep: Test 1 Section 9 Part 2. SAT Prep: Test 1 Section 9 Part 3. SAT Prep: Test 1 Section 9 Part 4. SAT Prep: Test 1 Section 9 Part 5. SAT Prep: Test 2 Section 3 part 1. SAT Prep: Test 2 Section 3 Part 2. SAT Prep: Test 2 Section 3 Part 3. SAT Prep: Test 2 Section 3 Part 4. SAT Prep: Test 2 Section 3 Part 5. SAT Prep: Test 2 Section 3 Part 6. SAT Prep: Test 2 Section 6 Part 1. SAT Prep: Test 2 Section 6 Part 2. SAT Prep: Test 2 Section 6 Part 3. SAT Prep: Test 2 Section 6 Part 4. SAT Prep: Test 2 Section 6 Part 5. SAT Prep: Test 2 Section 6 Part 6. SAT Prep: Test 2 Section 9 Part 1. SAT Prep: Test 2 Section 9 Part 2. SAT Prep: Test 2 Section 9 Part 3. SAT Prep: Test 2 Section 9 Part 4. SAT Prep: Test 3 Section 2 Part 1. SAT Prep: Test 3 Section 2 Part 2. SAT Prep: Test 3 Section 2 Part 3. SAT Prep: Test 3 Section 2 Part 4. Test 3 Section 2 Part 5. SAT Prep: Test 3 Section 4 Part 1. SAT Prep: Test 3 Section 4 Part 2. SAT Prep: Test 3 Section 4 Part 3. SAT Prep: Test 3 Section 4 Part 4. SAT Prep: Test 3 Section 4 Part 5. SAT Prep: Test 3 Section 8 Part 1. SAT Prep: Test 3 Section 8 Part 2. SAT Prep: Test 3 Section 8 Part 3. SAT Prep: Test 3 Section 8 Part 4. SAT Prep: Test 4 Section 2 Part 1. SAT Prep: Test 4 Section 2 Part 2. SAT Prep: Test 4 Section 2 Part 3. SAT Prep: Test 4 Section 2 Part 4. SAT Prep: Test 4 Section 2 Part 5. SAT Prep: Test 4 Section 2 Part 6. SAT Prep: Test 4 Section 4 Part 1. SAT Prep: Test 4 Section 4 Part 2. SAT Prep: Test 4 Section 4 Part 3. SAT Prep: Test 4 Section 4 Part 4. SAT Prep: Test 4 Section 8 Part 1. SAT Prep: Test 4 Section 8 Part 2. SAT Prep: Test 4 Section 8 Part 3. SAT Prep: Test 4 Section 8 Part 4. SAT Prep: Test 5 Section 3 Part 1. SAT Prep: Test 5 Section 3 Part 2. SAT Prep: Test 5 Section 3 Part 3. SAT Prep: Test 5 Section 3 Part 4. SAT Prep: Test 5 Section 3 Part 5. SAT Prep: Test 5 Section 3 Part 6. SAT Prep: Test 5 Section 7 Part 1. SAT Prep: Test 5 Section 7 Part 2. SAT Prep: Test 5 Section 7 Part 3. SAT Prep: Test 5 Section 7 Part 4. SAT Prep: Test 5 Section 7 Part 5. SAT Prep: Test 5 Section 7 Part 6. SAT Prep: Test 5 Section 9 Part 1. SAT Prep: Test 5 Section 9 Part 2. SAT Prep: Test 5 Section 9 Part 3. SAT Prep: Test 5 Section 9 Part 4. SAT Prep: Test 6 Section 3 Part 1. SAT Prep: Test 6 Section 3 Part 2. SAT Prep: Test 6 Section 3 Part 3. SAT Prep: Test 6 Section 3 Part 4. SAT Prep: Test 6 Section 3 Part 5. SAT Prep: Test 6 Section 7 Part 1. SAT Prep: Test 6 Section 7 Part 2. SAT Prep: Test 6 Section 7 Part 3. SAT Prep: Test 6 Section 7 Part 4. SAT Prep: Test 6 Section 7 Part 5. SAT Prep: Test 6 Section 7 Part 6. SAT Prep: Test 6 Section 9 Part 1. SAT Prep: Test 6 Section 9 Part 2. SAT Prep: Test 6 Section 9 Part 3. SAT Prep: Test 6 Section 9 Part 4. SAT Prep: Test 7 Section 2 Part 1. SAT Prep: Test 7 Section 2 Part 2. SAT Prep: Test 7 Section 2 Part 3. SAT Prep: Test 7 Section 2 Part 4. SAT Prep: Test 7 Section 5 Part 1. SAT Prep: Test 7 Section 5 Part 2. SAT Prep: Test 7 Section 5 Part 3. SAT Prep: Test 7 Section 5 Part 4. SAT Prep: Test 7 Section 5 Part 5. SAT Prep: Test 7 Section 8 Part 1. SAT Prep: Test 7 Section 8 Part 2. SAT Prep: Test 7 Section 8 Part 3. SAT Prep: Test 7 Section 8 Part 4. SAT Prep: Test 8 Section 2 Part 1. SAT Prep: Test 8 Section 2 Part 2. SAT Prep: Test 8 Section 2 Part 3. SAT Prep: Test 8 Section 2 Part 4. SAT Prep: Test 8 Section 5 Part 1. SAT Prep: Test 8 Section 5 Part 2. SAT Prep: Test 8 Section 5 Part 3. SAT Prep: Test 8 Section 5 Part 4. SAT Prep: Test 8 Section 8 Part 1. SAT Prep: Test 8 Section 8 Part 2. SAT Prep: Test 8 Section 8 Part 3. SAT prep: test 1 section3 part 1. SAT Prep: Test 1 Section 3 Part 2. SAT Prep: Test 1 Section 3 Part 3. SAT Prep: Test 1 Section 3 Part 4. SAT Prep: Test 1 Section 3 Part 5. SAT Prep: Test 1 Section 3 Part 6. SAT Prep: Test 1 Section 3 Part 7. SAT Prep: Test 1 Section 3 Part 8. SAT Prep: Test 1 Section 6 Part 1. SAT Prep: Test 1 Section 6 Part 2. SAT Prep: Test 1 Section 6 Part 3. SAT Prep: Test 1 Section 6 Part 4. SAT Prep: Test 1 Section 6 Part 5. SAT Prep: Test 1 Section 6 Part 6. SAT Prep: Test 1 Section 9 Part 1. SAT Prep: Test 1 Section 9 Part 2. SAT Prep: Test 1 Section 9 Part 3. SAT Prep: Test 1 Section 9 Part 4. SAT Prep: Test 1 Section 9 Part 5. SAT Prep: Test 2 Section 3 part 1. SAT Prep: Test 2 Section 3 Part 2. SAT Prep: Test 2 Section 3 Part 3. SAT Prep: Test 2 Section 3 Part 4. SAT Prep: Test 2 Section 3 Part 5. SAT Prep: Test 2 Section 3 Part 6. SAT Prep: Test 2 Section 6 Part 1. SAT Prep: Test 2 Section 6 Part 2. SAT Prep: Test 2 Section 6 Part 3. SAT Prep: Test 2 Section 6 Part 4. SAT Prep: Test 2 Section 6 Part 5. SAT Prep: Test 2 Section 6 Part 6. SAT Prep: Test 2 Section 9 Part 1. SAT Prep: Test 2 Section 9 Part 2. SAT Prep: Test 2 Section 9 Part 3. SAT Prep: Test 2 Section 9 Part 4. SAT Prep: Test 3 Section 2 Part 1. SAT Prep: Test 3 Section 2 Part 2. SAT Prep: Test 3 Section 2 Part 3. SAT Prep: Test 3 Section 2 Part 4. Test 3 Section 2 Part 5. SAT Prep: Test 3 Section 4 Part 1. SAT Prep: Test 3 Section 4 Part 2. SAT Prep: Test 3 Section 4 Part 3. SAT Prep: Test 3 Section 4 Part 4. SAT Prep: Test 3 Section 4 Part 5. SAT Prep: Test 3 Section 8 Part 1. SAT Prep: Test 3 Section 8 Part 2. SAT Prep: Test 3 Section 8 Part 3. SAT Prep: Test 3 Section 8 Part 4. SAT Prep: Test 4 Section 2 Part 1. SAT Prep: Test 4 Section 2 Part 2. SAT Prep: Test 4 Section 2 Part 3. SAT Prep: Test 4 Section 2 Part 4. SAT Prep: Test 4 Section 2 Part 5. SAT Prep: Test 4 Section 2 Part 6. SAT Prep: Test 4 Section 4 Part 1. SAT Prep: Test 4 Section 4 Part 2. SAT Prep: Test 4 Section 4 Part 3. SAT Prep: Test 4 Section 4 Part 4. SAT Prep: Test 4 Section 8 Part 1. SAT Prep: Test 4 Section 8 Part 2. SAT Prep: Test 4 Section 8 Part 3. SAT Prep: Test 4 Section 8 Part 4. SAT Prep: Test 5 Section 3 Part 1. SAT Prep: Test 5 Section 3 Part 2. SAT Prep: Test 5 Section 3 Part 3. SAT Prep: Test 5 Section 3 Part 4. SAT Prep: Test 5 Section 3 Part 5. SAT Prep: Test 5 Section 3 Part 6. SAT Prep: Test 5 Section 7 Part 1. SAT Prep: Test 5 Section 7 Part 2. SAT Prep: Test 5 Section 7 Part 3. SAT Prep: Test 5 Section 7 Part 4. SAT Prep: Test 5 Section 7 Part 5. SAT Prep: Test 5 Section 7 Part 6. SAT Prep: Test 5 Section 9 Part 1. SAT Prep: Test 5 Section 9 Part 2. SAT Prep: Test 5 Section 9 Part 3. SAT Prep: Test 5 Section 9 Part 4. SAT Prep: Test 6 Section 3 Part 1. SAT Prep: Test 6 Section 3 Part 2. SAT Prep: Test 6 Section 3 Part 3. SAT Prep: Test 6 Section 3 Part 4. SAT Prep: Test 6 Section 3 Part 5. SAT Prep: Test 6 Section 7 Part 1. SAT Prep: Test 6 Section 7 Part 2. SAT Prep: Test 6 Section 7 Part 3. SAT Prep: Test 6 Section 7 Part 4. SAT Prep: Test 6 Section 7 Part 5. SAT Prep: Test 6 Section 7 Part 6. SAT Prep: Test 6 Section 9 Part 1. SAT Prep: Test 6 Section 9 Part 2. SAT Prep: Test 6 Section 9 Part 3. SAT Prep: Test 6 Section 9 Part 4. SAT Prep: Test 7 Section 2 Part 1. SAT Prep: Test 7 Section 2 Part 2. SAT Prep: Test 7 Section 2 Part 3. SAT Prep: Test 7 Section 2 Part 4. SAT Prep: Test 7 Section 5 Part 1. SAT Prep: Test 7 Section 5 Part 2. SAT Prep: Test 7 Section 5 Part 3. SAT Prep: Test 7 Section 5 Part 4. SAT Prep: Test 7 Section 5 Part 5. SAT Prep: Test 7 Section 8 Part 1. SAT Prep: Test 7 Section 8 Part 2. SAT Prep: Test 7 Section 8 Part 3. SAT Prep: Test 7 Section 8 Part 4. SAT Prep: Test 8 Section 2 Part 1. SAT Prep: Test 8 Section 2 Part 2. SAT Prep: Test 8 Section 2 Part 3. SAT Prep: Test 8 Section 2 Part 4. SAT Prep: Test 8 Section 5 Part 1. SAT Prep: Test 8 Section 5 Part 2. SAT Prep: Test 8 Section 5 Part 3. SAT Prep: Test 8 Section 5 Part 4. SAT Prep: Test 8 Section 8 Part 1. SAT Prep: Test 8 Section 8 Part 2. SAT Prep: Test 8 Section 8 Part 3.

Hank Green teaches you ecology!. The History of Life on Earth. Population Ecology: The Texas Mosquito Mystery. Human Population Growth. Community Ecology: Feel the Love. Community Ecology II: Predators. Ecological Succession: Change is Good. Ecosystem Ecology: Links in the Chain. The Hydrologic and Carbon Cycles: Always Recycle!. Nitrogen and Phosphorus Cycles: Always Recycle!. 5 Human Impacts on the Environment. Pollution. Conservation and Restoration Ecology. The History of Life on Earth. Population Ecology: The Texas Mosquito Mystery. Human Population Growth. Community Ecology: Feel the Love. Community Ecology II: Predators. Ecological Succession: Change is Good. Ecosystem Ecology: Links in the Chain. The Hydrologic and Carbon Cycles: Always Recycle!. Nitrogen and Phosphorus Cycles: Always Recycle!. 5 Human Impacts on the Environment. Pollution. Conservation and Restoration Ecology.

Hank Green teaches you biology!. Why Carbon is a Tramp. Water - Liquid Awesome. Biological Molecules - You Are What You Eat. Eukaryopolis - The City of Animal Cells. In Da Club - Membranes & Transport. Plant Cells. ATP & Respiration. Photosynthesis. Heredity. DNA Structure and Replication. DNA, Hot Pockets, & The Longest Word Ever. Mitosis: Splitting Up is Complicated. Meiosis: Where the Sex Starts. Natural Selection. Speciation: Of Ligers & Men. Animal Development: We're Just Tubes. Evolutionary Development: Chicken Teeth. Population Genetics: When Darwin Met Mendel. Taxonomy: Life's Filing System. Evolution: It's a Thing. Comparative Anatomy: What Makes Us Animals. Simple Animals: Sponges, Jellies, & Octopuses. Complex Animals: Annelids & Arthropods. Chordates. Animal Behavior. The Nervous System. Circulatory & Respiratory Systems. The Digestive System. The Excretory System: From Your Heart to the Toilet. The Skeletal System: It's ALIVE!. Big Guns: The Muscular System. Your Immune System: Natural Born Killer. Great Glands - Your Endocrine System. The Reproductive System: How Gonads Go. Old & Odd: Archaea, Bacteria & Protists. The Sex Lives of Nonvascular Plants. Vascular Plants = Winning!. The Plants & The Bees: Plant Reproduction. Fungi: Death Becomes Them. Ecology - Rules for Living on Earth. Why Carbon is a Tramp. Water - Liquid Awesome. Biological Molecules - You Are What You Eat. Eukaryopolis - The City of Animal Cells. In Da Club - Membranes & Transport. Plant Cells. ATP & Respiration. Photosynthesis. Heredity. DNA Structure and Replication. DNA, Hot Pockets, & The Longest Word Ever. Mitosis: Splitting Up is Complicated. Meiosis: Where the Sex Starts. Natural Selection. Speciation: Of Ligers & Men. Animal Development: We're Just Tubes. Evolutionary Development: Chicken Teeth. Population Genetics: When Darwin Met Mendel. Taxonomy: Life's Filing System. Evolution: It's a Thing. Comparative Anatomy: What Makes Us Animals. Simple Animals: Sponges, Jellies, & Octopuses. Complex Animals: Annelids & Arthropods. Chordates. Animal Behavior. The Nervous System. Circulatory & Respiratory Systems. The Digestive System. The Excretory System: From Your Heart to the Toilet. The Skeletal System: It's ALIVE!. Big Guns: The Muscular System. Your Immune System: Natural Born Killer. Great Glands - Your Endocrine System. The Reproductive System: How Gonads Go. Old & Odd: Archaea, Bacteria & Protists. The Sex Lives of Nonvascular Plants. Vascular Plants = Winning!. The Plants & The Bees: Plant Reproduction. Fungi: Death Becomes Them. Ecology - Rules for Living on Earth.

John Green teaches you the history of the world in 42 episodes of Crash Course. The Agricultural Revolution. Indus Valley Civilization. Ancient Mesopotamia. Ancient Egypt. Greeks and Persians. Buddha and Ashoka. 2000 Years of Chinese History! The Mandate of Heaven and Confuscius. Alexander the Great and the Situation... the Great?. The Silk Road and Ancient Trade. The Roman Empire. Or Republic. Or... Which Was It?. Christianity from Judaism to Constantine. Fall of Rome the Roman Empire... in the 15th Century. Islam, the Quran, and the Five Pillars All Without a Flamewar. The Dark Ages...How Dark Were They, Really?. The Crusades - Pilgrimage or Holy War?. Mansa Musa and Islam in Africa. Wait for it... The Mongols!. International Commerce, Snorkeling Camels, and The Indian Ocean Trade. Venice and the Ottoman Empire. Russia, the Kievan Rus, and the Mongols. Columbus, de Gama, and Zheng He! 15th Century Mariners. The Renaissance: Was it a Thing?. The Columbian Exchange. The Atlantic Slave Trade. The Spanish Empire, Silver, & Runaway Inflation. The Seven Years War. The Amazing Life and Strange Death of Captain Cook. Tea, Taxes, and The American Revolution. The French Revolution. The Haitian Revolutions. Latin American Revolutions. Coal, Steam, and The Industrial Revolution. Capitalism and Socialism. Samurai, Daimyo, Matthew Perry, and Nationalism. Imperialism. Archdukes, Cynicism, and World War I. Communists, Nationalists, and China's Revolutions. World War II. USA vs USSR Fight! The Cold War. Decolonization and Nationalism Triumphant. Globalization I - The Upside. Globalization II - Good or Bad?. The Agricultural Revolution. Indus Valley Civilization. Ancient Mesopotamia. Ancient Egypt. Greeks and Persians. Buddha and Ashoka. 2000 Years of Chinese History! The Mandate of Heaven and Confuscius. Alexander the Great and the Situation... the Great?. The Silk Road and Ancient Trade. The Roman Empire. Or Republic. Or... Which Was It?. Christianity from Judaism to Constantine. Fall of Rome the Roman Empire... in the 15th Century. Islam, the Quran, and the Five Pillars All Without a Flamewar. The Dark Ages...How Dark Were They, Really?. The Crusades - Pilgrimage or Holy War?. Mansa Musa and Islam in Africa. Wait for it... The Mongols!. International Commerce, Snorkeling Camels, and The Indian Ocean Trade. Venice and the Ottoman Empire. Russia, the Kievan Rus, and the Mongols. Columbus, de Gama, and Zheng He! 15th Century Mariners. The Renaissance: Was it a Thing?. The Columbian Exchange. The Atlantic Slave Trade. The Spanish Empire, Silver, & Runaway Inflation. The Seven Years War. The Amazing Life and Strange Death of Captain Cook. Tea, Taxes, and The American Revolution. The French Revolution. The Haitian Revolutions. Latin American Revolutions. Coal, Steam, and The Industrial Revolution. Capitalism and Socialism. Samurai, Daimyo, Matthew Perry, and Nationalism. Imperialism. Archdukes, Cynicism, and World War I. Communists, Nationalists, and China's Revolutions. World War II. USA vs USSR Fight! The Cold War. Decolonization and Nationalism Triumphant. Globalization I - The Upside. Globalization II - Good or Bad?.

2003 AIME II Problem 1. 2003 AIME II Problem 3. Sum of factors of 27000. Sum of factors 2. 2003 AIME II Problem 4 (part 1). 2003 AIME II Problem 4 (part 2). 2003 AIME II Problem 5. 2003 AIME II Problem 5 Minor Correction. Area Circumradius Formula Proof. 2003 AIME II Problem 6. 2003 AIME II Problem 7. 2003 AIME II Problem 8. Sum of Polynomial Roots (Proof). Sum of Squares of Polynomial Roots. 2003 AIME II Problem 9. 2003 AIME II Problem 10. 2003 AIME II Problem 11. 2003 AIME II Problem 12. 2003 AIME II Problem 13. 2003 AIME II Problem 14. 2003 AIME II Problem 15 (part 1). 2003 AIME II Problem 15 (part 2). 2003 AIME II Problem 15 (part 3). 2003 AIME II Problem 1. 2003 AIME II Problem 3. Sum of factors of 27000. Sum of factors 2. 2003 AIME II Problem 4 (part 1). 2003 AIME II Problem 4 (part 2). 2003 AIME II Problem 5. 2003 AIME II Problem 5 Minor Correction. Area Circumradius Formula Proof. 2003 AIME II Problem 6. 2003 AIME II Problem 7. 2003 AIME II Problem 8. Sum of Polynomial Roots (Proof). Sum of Squares of Polynomial Roots. 2003 AIME II Problem 9. 2003 AIME II Problem 10. 2003 AIME II Problem 11. 2003 AIME II Problem 12. 2003 AIME II Problem 13. 2003 AIME II Problem 14. 2003 AIME II Problem 15 (part 1). 2003 AIME II Problem 15 (part 2). 2003 AIME II Problem 15 (part 3).

The AMC 10 is part of the series of contests administered by the MAA American Mathematics Competitions that determines the United States team in the International Math Olympiad. The AMC 10 is a 25 question, 75 minute multiple choice test for students in 10th grade or below. Two versions of the AMC 10 are offered each year. 2013 AMC 10 A #21 / AMC 12 A #17. 2013 AMC 10 A #22 / AMC 12 A #18. 2013 AMC 10 A #23 / AMC 12 A #19. 2013 AMC 10 A #24. 2013 AMC 10 A #25. 2013 AMC 10 A #21 / AMC 12 A #17. 2013 AMC 10 A #22 / AMC 12 A #18. 2013 AMC 10 A #23 / AMC 12 A #19. 2013 AMC 10 A #24. 2013 AMC 10 A #25.

What ratios and proportions are. Using them to solve problems in the real world. Ratio problem with basic algebra (new HD). Writing proportions. Writing proportions. Find an Unknown in a Proportion. Find an Unknown in a Proportion 2. Proportions 1. Proportions 2 exercise examples. Proportions 2. Constructing proportions to solve application problems. Constructing proportions to solve application problems. The Golden Ratio. Advanced ratio problems. More advanced ratio problem--with Algebra (HD version). Another Take on the Rate Problem. Alternate Solution to Ratio Problem (HD Version). Mountain height word problem. Ratio problem with basic algebra (new HD). Writing proportions. Writing proportions. Find an Unknown in a Proportion. Find an Unknown in a Proportion 2. Proportions 1. Proportions 2 exercise examples. Proportions 2. Constructing proportions to solve application problems. Constructing proportions to solve application problems. The Golden Ratio. Advanced ratio problems. More advanced ratio problem--with Algebra (HD version). Another Take on the Rate Problem. Alternate Solution to Ratio Problem (HD Version). Mountain height word problem.

60 minutes: Khan Academy's "world-changing" plan for schools. 60 minutes: Google's Eric Schmidt on Khan Academy. 60 minutes: School of the future. 60 minutes: Khan Academy in the classroom. 60 minutes: Khan Academy's "world-changing" plan for schools. 60 minutes: Google's Eric Schmidt on Khan Academy. 60 minutes: School of the future. 60 minutes: Khan Academy in the classroom.

Elizabeth Slavitt. Marcos Ojeda. Minli Virdone. Jessica Yuen. Elizabeth Slavitt. Marcos Ojeda. Minli Virdone. Jessica Yuen.

Salman Khan talk at TED 2011 (from ted.com). 60 minutes: The future of education?. Salman Khan on Charlie Rose 2013. Bill Gates talks about the Khan Academy at Aspen Ideas Festival 2010. Salman Khan talk at TED 2011 (from ted.com). 60 minutes: The future of education?. Salman Khan on Charlie Rose 2013. Bill Gates talks about the Khan Academy at Aspen Ideas Festival 2010.

Khan Academy at Marlborough School. Khan Academy at Oakland Unity High School. Khan Academy at Summit Prep. Khan Academy at Eastside College Prep. Khan Academy in Los Altos School District. Khan Academy at KIPP. Khan Academy at Marlborough School. Khan Academy at Oakland Unity High School. Khan Academy at Summit Prep. Khan Academy at Eastside College Prep. Khan Academy in Los Altos School District. Khan Academy at KIPP.

Khan Academy Vision and Social Return. Videocast with Sal Khan: Effectively Using Khan Academy. KA on John Stossel Documentary. Khan Academy on Perry's Principles (6/2/2011). ED SESSION III with Sal Khan - Reactions in Idaho. Salman Khan on CNN. Salman Khan at TiEcon 2011. PBS NewsHour on the Khan Academy. Salman Khan Speaks at GEL (Good Experience Live) Conference. Salman Khan Talk at the MIT Club of Northern California. Salman Khan talk at Castilleja School on January 5th, 2010. Sal Khan Interview with IT Conversations - January 31,2010. Salman Khan interview with NPR's All Things Considered on 12/28/2009. Salman Khan Interview with Mixergy.com. Brian Lehrer Interview with Salman Khan. TEDxSanJoseCA - Salman Khan - (Sequel to talk at TED). Bay Area CBS Station with Salman Khan. Fareed Zakaria talks about Khan Academy on CNN GPS. Sal on Dylan Ratigan show. Khan Academy on the Gates Notes. LinkedIn Speaker Series Salman Khan. Forbes Names You Need To Know: Khan Academy. Salman Khan on Big Think. Khan Academy on 20/20 (Sep 2011). Salman Khan on Marketplace (NPR) on 5-24-2011. May 29th, 2011 CNN Piece. Sal during Education Week (Sep 2011) 1. Khan Academy on California Report (June 2011). Ideal Math and Science Class Time. Salman Khan on KQED MindShift. NPR Story on KA Los Altos Pilots (June 2011). Salman Khan interviewed on NPR's On Point. 21st Century Challenges (Royal Geographic Society). Answers to Questions from the Independent. Answers for Malibu Magazine. NCSU Answers. Questions from Superinteressante (8-22-2011). Brainwave Sep 2011. Center for Future of Museums. School Leadership Briefing Questions (Sep 12 2011) 2. School Leadership Briefing (Sep 12 2011). Tom Brokaw interviews Sal at Education Nation 2011. Financial Times October 2011. Verbal Answers to "Ask Me Anything" on Reddit. Khan Academy in Idaho. The Language Advocates. Jessica Yuen. Marcos Ojeda. Elizabeth Slavitt. Minli Virdone. Ideal Math and Science Class Time. Salman Khan on Charlie Rose. Nightline: Learn Everything, Online. Khan Academy on PBS NewsHour (Edited). Khan Academy on Nightly News. Early Show. Sal on ABC News. CNN: Google award to Khan Academy. Videocast with Sal Khan: Effectively Using Khan Academy. Overview of KhanAcademy.org. Khan Academy Vision and Social Return. Videocast with Sal Khan: Effectively Using Khan Academy. KA on John Stossel Documentary. Khan Academy on Perry's Principles (6/2/2011). ED SESSION III with Sal Khan - Reactions in Idaho. Salman Khan on CNN. Salman Khan at TiEcon 2011. PBS NewsHour on the Khan Academy. Salman Khan Speaks at GEL (Good Experience Live) Conference. Salman Khan Talk at the MIT Club of Northern California. Salman Khan talk at Castilleja School on January 5th, 2010. Sal Khan Interview with IT Conversations - January 31,2010. Salman Khan interview with NPR's All Things Considered on 12/28/2009. Salman Khan Interview with Mixergy.com. Brian Lehrer Interview with Salman Khan. TEDxSanJoseCA - Salman Khan - (Sequel to talk at TED). Bay Area CBS Station with Salman Khan. Fareed Zakaria talks about Khan Academy on CNN GPS. Sal on Dylan Ratigan show. Khan Academy on the Gates Notes. LinkedIn Speaker Series Salman Khan. Forbes Names You Need To Know: Khan Academy. Salman Khan on Big Think. Khan Academy on 20/20 (Sep 2011). Salman Khan on Marketplace (NPR) on 5-24-2011. May 29th, 2011 CNN Piece. Sal during Education Week (Sep 2011) 1. Khan Academy on California Report (June 2011). Ideal Math and Science Class Time. Salman Khan on KQED MindShift. NPR Story on KA Los Altos Pilots (June 2011). Salman Khan interviewed on NPR's On Point. 21st Century Challenges (Royal Geographic Society). Answers to Questions from the Independent. Answers for Malibu Magazine. NCSU Answers. Questions from Superinteressante (8-22-2011). Brainwave Sep 2011. Center for Future of Museums. School Leadership Briefing Questions (Sep 12 2011) 2. School Leadership Briefing (Sep 12 2011). Tom Brokaw interviews Sal at Education Nation 2011. Financial Times October 2011. Verbal Answers to "Ask Me Anything" on Reddit. Khan Academy in Idaho. The Language Advocates. Jessica Yuen. Marcos Ojeda. Elizabeth Slavitt. Minli Virdone. Ideal Math and Science Class Time. Salman Khan on Charlie Rose. Nightline: Learn Everything, Online. Khan Academy on PBS NewsHour (Edited). Khan Academy on Nightly News. Early Show. Sal on ABC News. CNN: Google award to Khan Academy. Videocast with Sal Khan: Effectively Using Khan Academy. Overview of KhanAcademy.org.