Online courses directory (381)

Introduction to probability. Independent and dependent events. Compound events. Mutual exclusive events. Addition rule for probability. Basic Probability. Probability space exercise example. Probability space. Example: Marbles from a bag. Example: Picking a non-blue marble. Example: Picking a yellow marble. Probability 1. Probability with Playing Cards and Venn Diagrams. Addition Rule for Probability. Compound Probability of Independent Events. Getting At Least One Heads. Example: Probability of rolling doubles. LeBron Asks: What are the chances of making 10 free throws in a row?. LeBron Asks: What are the chances of three free throws versus one three pointer?. Frequency Probability and Unfair Coins. Example: Getting two questions right on an exam. Example: Rolling even three times. Independent probability. Frequency Stability. Introduction to dependent probability. Example: Dependent probability. Example: Is an event independent or dependent?. Example: Bag of unfair coins. Dependent probability. Monty Hall Problem. Intersection and union of sets. Relative complement or difference between sets. Universal set and absolute complement. Subset, strict subset, and superset. Bringing the set operations together. Basic set notation. Probability (part 1). Probability (part 2). Probability (part 3). Probability (part 4). Probability (part 5). Probability (part 6). Probability (part 7). Probability (part 8). Introduction to Random Variables. Basic Probability. Probability space exercise example. Probability space. Example: Marbles from a bag. Example: Picking a non-blue marble. Example: Picking a yellow marble. Probability 1. Probability with Playing Cards and Venn Diagrams. Addition Rule for Probability. Compound Probability of Independent Events. Getting At Least One Heads. Example: Probability of rolling doubles. LeBron Asks: What are the chances of making 10 free throws in a row?. LeBron Asks: What are the chances of three free throws versus one three pointer?. Frequency Probability and Unfair Coins. Example: Getting two questions right on an exam. Example: Rolling even three times. Independent probability. Frequency Stability. Introduction to dependent probability. Example: Dependent probability. Example: Is an event independent or dependent?. Example: Bag of unfair coins. Dependent probability. Monty Hall Problem. Intersection and union of sets. Relative complement or difference between sets. Universal set and absolute complement. Subset, strict subset, and superset. Bringing the set operations together. Basic set notation. Probability (part 1). Probability (part 2). Probability (part 3). Probability (part 4). Probability (part 5). Probability (part 6). Probability (part 7). Probability (part 8). Introduction to Random Variables.

Making inferences based on sample data. Confidence intervals. Margin of error. Hypothesis testing. Introduction to the Normal Distribution. Normal Distribution Excel Exercise. ck12.org Normal Distribution Problems: Qualitative sense of normal distributions. ck12.org Normal Distribution Problems: Empirical Rule. ck12.org Normal Distribution Problems: z-score. ck12.org Exercise: Standard Normal Distribution and the Empirical Rule. Empirical rule. ck12.org: More Empirical Rule and Z-score practice. Z scores 1. Z scores 2. Z scores 3. Central Limit Theorem. Sampling Distribution of the Sample Mean. Sampling Distribution of the Sample Mean 2. Standard Error of the Mean. Sampling Distribution Example Problem. Confidence Interval 1. Confidence Interval Example. Small Sample Size Confidence Intervals. Mean and Variance of Bernoulli Distribution Example. Bernoulli Distribution Mean and Variance Formulas. Margin of Error 1. Margin of Error 2. Hypothesis Testing and P-values. One-Tailed and Two-Tailed Tests. Type 1 Errors. Z-statistics vs. T-statistics. Small Sample Hypothesis Test. T-Statistic Confidence Interval. Large Sample Proportion Hypothesis Testing. Variance of Differences of Random Variables. Difference of Sample Means Distribution. Confidence Interval of Difference of Means. Clarification of Confidence Interval of Difference of Means. Hypothesis Test for Difference of Means. Comparing Population Proportions 1. Comparing Population Proportions 2. Hypothesis Test Comparing Population Proportions. Chi-Square Distribution Introduction. Pearson's Chi Square Test (Goodness of Fit). Contingency Table Chi-Square Test. ANOVA 1 - Calculating SST (Total Sum of Squares). ANOVA 2 - Calculating SSW and SSB (Total Sum of Squares Within and Between).avi. ANOVA 3 -Hypothesis Test with F-Statistic. Introduction to the Normal Distribution. Normal Distribution Excel Exercise. ck12.org Normal Distribution Problems: Qualitative sense of normal distributions. ck12.org Normal Distribution Problems: Empirical Rule. ck12.org Normal Distribution Problems: z-score. ck12.org Exercise: Standard Normal Distribution and the Empirical Rule. Empirical rule. ck12.org: More Empirical Rule and Z-score practice. Z scores 1. Z scores 2. Z scores 3. Central Limit Theorem. Sampling Distribution of the Sample Mean. Sampling Distribution of the Sample Mean 2. Standard Error of the Mean. Sampling Distribution Example Problem. Confidence Interval 1. Confidence Interval Example. Small Sample Size Confidence Intervals. Mean and Variance of Bernoulli Distribution Example. Bernoulli Distribution Mean and Variance Formulas. Margin of Error 1. Margin of Error 2. Hypothesis Testing and P-values. One-Tailed and Two-Tailed Tests. Type 1 Errors. Z-statistics vs. T-statistics. Small Sample Hypothesis Test. T-Statistic Confidence Interval. Large Sample Proportion Hypothesis Testing. Variance of Differences of Random Variables. Difference of Sample Means Distribution. Confidence Interval of Difference of Means. Clarification of Confidence Interval of Difference of Means. Hypothesis Test for Difference of Means. Comparing Population Proportions 1. Comparing Population Proportions 2. Hypothesis Test Comparing Population Proportions. Chi-Square Distribution Introduction. Pearson's Chi Square Test (Goodness of Fit). Contingency Table Chi-Square Test. ANOVA 1 - Calculating SST (Total Sum of Squares). ANOVA 2 - Calculating SSW and SSB (Total Sum of Squares Within and Between).avi. ANOVA 3 -Hypothesis Test with F-Statistic.

Permutations and combinations. Using combinatorics to solve questions in probability. Permutations. Combinations. Counting 2. Example: Ways to arrange colors. Example: 9 card hands. Example: Ways to pick officers. Permutations. Combinations. Permutations and combinations. Example: Probability through counting outcomes. Example: All the ways you can flip a coin. Getting Exactly Two Heads (Combinatorics). Probability and Combinations (part 2). Probability using Combinations. Exactly Three Heads in Five Flips. Example: Different ways to pick officers. Example: Combinatorics and probability. Example: Lottery probability. Mega Millions Jackpot Probability. Generalizing with Binomial Coefficients (bit advanced). Conditional Probability and Combinations. Conditional Probability (Bayes Theorem) Visualized. Birthday Probability Problem. Probability with permutations and combinations. Permutations. Combinations. Counting 2. Example: Ways to arrange colors. Example: 9 card hands. Example: Ways to pick officers. Permutations. Combinations. Permutations and combinations. Example: Probability through counting outcomes. Example: All the ways you can flip a coin. Getting Exactly Two Heads (Combinatorics). Probability and Combinations (part 2). Probability using Combinations. Exactly Three Heads in Five Flips. Example: Different ways to pick officers. Example: Combinatorics and probability. Example: Lottery probability. Mega Millions Jackpot Probability. Generalizing with Binomial Coefficients (bit advanced). Conditional Probability and Combinations. Conditional Probability (Bayes Theorem) Visualized. Birthday Probability Problem. Probability with permutations and combinations.

Random variables. Expected value. Probability distributions (both discrete and continuous). Binomial distribution. Poisson processes. Random Variables. Discrete and continuous random variables. Probability Density Functions. Expected Value: E(X). Expected value. Law of Large Numbers. Term Life Insurance and Death Probability. Binomial Distribution 1. Binomial Distribution 2. Binomial Distribution 3. Binomial Distribution 4. Expected Value of Binomial Distribution. Galton Board Exploration. Poisson Process 1. Poisson Process 2. Random Variables. Discrete and continuous random variables. Probability Density Functions. Expected Value: E(X). Expected value. Law of Large Numbers. Term Life Insurance and Death Probability. Binomial Distribution 1. Binomial Distribution 2. Binomial Distribution 3. Binomial Distribution 4. Expected Value of Binomial Distribution. Galton Board Exploration. Poisson Process 1. Poisson Process 2.

Fitting a line to points. Linear regression. R-squared. Correlation and Causality. Fitting a Line to Data. Estimating the line of best fit exercise. Estimating the line of best fit. Squared Error of Regression Line. Proof (Part 1) Minimizing Squared Error to Regression Line. Proof Part 2 Minimizing Squared Error to Line. Proof (Part 3) Minimizing Squared Error to Regression Line. Proof (Part 4) Minimizing Squared Error to Regression Line. Regression Line Example. Second Regression Example. R-Squared or Coefficient of Determination. Calculating R-Squared. Covariance and the Regression Line. Correlation and Causality. Fitting a Line to Data. Estimating the line of best fit exercise. Estimating the line of best fit. Squared Error of Regression Line. Proof (Part 1) Minimizing Squared Error to Regression Line. Proof Part 2 Minimizing Squared Error to Line. Proof (Part 3) Minimizing Squared Error to Regression Line. Proof (Part 4) Minimizing Squared Error to Regression Line. Regression Line Example. Second Regression Example. R-Squared or Coefficient of Determination. Calculating R-Squared. Covariance and the Regression Line.

The Power of the Docs. Pseudo-Code. Clarifying with Comments.

What is Programming?. Sneak Peek: Making An Awesome Program. A Tour of Programming on Khan Academy.

If Statements. More Mouse Interaction. Booleans. If/Else - Part 1. If/Else - Part 2.

Intro to Drawing. Challenge: H for Hopper. More Drawing!. Challenge: Simple Shapes!. Challenge: CRAZY Face. Intro to Coloring. Challenge: Ice Cream Code. Challenge: It's a Beautiful Day. Intro to Variables. Challenge: Bucktooth Bunny. More on Variables. Challenge: Funky Frog. Variable Expressions. Intro to Animation. Mouse Interaction. Incrementing Shortcuts. Using Math Expressions. Terrific Text: Part One. Terrific Text: Part Two.

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 Cube Law (deflection method). Inverse Square Relationship. Inverse Cube 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 Cube Law (deflection method). Inverse Square Relationship. Inverse Cube 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?.

Khan Academy's Discovery Lab Offers Hands-On Learning. Khan DL Week 3 - Vannesa, Melvin & Greta. Khan DL Week 2 - Philip and Miles. Khan DL Week 2 - Arshia. AntBots in action. Khan Academy's Discovery Lab Offers Hands-On Learning. Khan DL Week 3 - Vannesa, Melvin & Greta. Khan DL Week 2 - Philip and Miles. Khan DL Week 2 - Arshia. AntBots in action.

Discovery Lab Overview. Monty Hall. Icosahedron. Lemonade Stand. Magician's Guess. Bridge Building. Explore Instructor Reflections. Lego Sumo Robots. Rube Goldberg. Spout Bot Innovation. Spout Bot Build. Spout Comes Alive. Spout Instructor Reflections. Build Up to Bridge Testing. Exhibition Day. Discovery Lab Overview. Monty Hall. Icosahedron. Lemonade Stand. Magician's Guess. Bridge Building. Explore Instructor Reflections. Lego Sumo Robots. Rube Goldberg. Spout Bot Innovation. Spout Bot Build. Spout Comes Alive. Spout Instructor Reflections. Build Up to Bridge Testing. Exhibition Day.

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.

Videos exploring the way things work. What is inside an alarm clock radio?. What is inside a coffee maker?. What is inside a tap light?. What is inside a hair dryer? (1 of 2). What is inside a hair dryer? (2 of 2). Compare the hair dryer motor to the one you can build. What is inside a DVD player? (1 of 5). What is inside a DVD player? (2 of 5). What is inside a DVD player? (3 of 5). What is inside a DVD player? (4 of 5). What is inside a DVD player? (5 of 5). What is inside a universal remote control?. What is inside a digital camera? (1 of 2). What is inside a digital camera? (2 of 2). What is inside an alarm clock radio?. What is inside a coffee maker?. What is inside a tap light?. What is inside a hair dryer? (1 of 2). What is inside a hair dryer? (2 of 2). Compare the hair dryer motor to the one you can build. What is inside a DVD player? (1 of 5). What is inside a DVD player? (2 of 5). What is inside a DVD player? (3 of 5). What is inside a DVD player? (4 of 5). What is inside a DVD player? (5 of 5). What is inside a universal remote control?. What is inside a digital camera? (1 of 2). What is inside a digital camera? (2 of 2).

Start your own robotics project with Spout, Spider, and Bit-zee!. 3rd graders build robots at Santa Rita Elementary School. Parts list for Spout. Tool list for Spout. Spout step by step PDF. 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. Spout OOP: with Maze. The goal of Spout. 1 Spout Introduction (with solder). 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. 6th graders learn to build a Spider robot. Fun with a Spider Bot. Parts list for Spider. Tools 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. Parts for Bit-zee and It-zee. Tools for Bit-zee and It-zee. 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. 3rd graders build robots at Santa Rita Elementary School. Parts list for Spout. Tool list for Spout. Spout step by step PDF. 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. Spout OOP: with Maze. The goal of Spout. 1 Spout Introduction (with solder). 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. 6th graders learn to build a Spider robot. Fun with a Spider Bot. Parts list for Spider. Tools 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. Parts for Bit-zee and It-zee. Tools for Bit-zee and It-zee. 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.

Thermo Can. Thermo Can.

This project is a low cost robot made from every day items that are taken apart and described in the reverse engineering section. 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.

In this section we investigate how dc motors work and what is inside of them. Brushed DC motor explained. Build your own motor. Compare the hair dryer motor to the one you can build.

Brushed DC motor explained. Build your own motor. Compare the hair dryer motor to the one you can build.

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?.