Magnets and magnetic fields; electromagnets

Interactive lesson
Poles are where the effect is strongestInteractive lesson
Attract or repel? The facing poles decideInteractive lesson
The magnetic materialsInteractive lesson
Magnet versus magnetic materialInteractive lesson
The repulsion testVideo lesson
How a magnet attracts something that is not a magnetInteractive lesson
Permanent and temporary magnetsInteractive lesson
A compass is a tiny magnetInteractive lesson
What the field-line direction meansInteractive lesson
Read a field diagramInteractive lesson
Earth's magnetic fieldVideo lesson
Currents make magnetic fields

Electromagnets

Interactive lesson
The field around a straight wireInteractive lesson
Grip rule for a straight wireInteractive lesson
More current, stronger fieldInteractive lesson
Further away, weaker fieldInteractive lesson
A coil's field looks like a bar magnet'sInteractive lesson
Which face of a coil is northInteractive lesson
Sketch a solenoid's fieldInteractive lesson
What an electromagnet isInteractive lesson
More turns, stronger electromagnetInteractive lesson
The core makes it strongerInteractive lesson
Electromagnets can be switched offInteractive lesson
Electromagnets can change strength

The motor effect

Interactive lesson
The motor effectInteractive lesson
When the force disappearsVideo lesson
Fleming's left-hand ruleInteractive lesson
Stronger field, bigger forceInteractive lesson
A bigger current means a bigger forceInteractive lesson
Longer wire in the field, bigger forceInteractive lesson
Rank the motor-effect forcesInteractive lesson
Moving charges feel the forceInteractive lesson
No motion, no magnetic forceInteractive lesson
Why the aurora happens at the polesInteractive lesson
How an electric motor turnsInteractive lesson
A motor's energy transfer

Electromagnetic induction

Interactive lesson
Moving a magnet makes a voltageInteractive lesson
Naming the induced EMFInteractive lesson
EMF without currentInteractive lesson
Moving the wire works tooVideo lesson
One coil can induce in anotherInteractive lesson
The one condition for inductionInteractive lesson
No change, no EMFInteractive lesson
Lenz's lawInteractive lesson
Predict the induced directionInteractive lesson
Why Lenz must be trueInteractive lesson
Faster change, bigger EMF

Generators and alternating current

Interactive lesson
Stronger field, bigger EMFInteractive lesson
More turns, bigger EMFInteractive lesson
Rank the induced EMFsInteractive lesson
The generator effect, the motor effect reversedInteractive lesson
Motor effect or generator effect?Interactive lesson
Direct and alternating currentInteractive lesson
What a generator isInteractive lesson
A generator's energy transferInteractive lesson
Why a spinning coil makes ACInteractive lesson
Spin it faster

Transformers and power transmission

Interactive lesson
What a transformer is made ofInteractive lesson
How a transformer worksInteractive lesson
Why transformers need ACInteractive lesson
Step-up or step-downInteractive lesson
The turns-ratio equationInteractive lesson
Find the missing voltageInteractive lesson
Find the missing turnsInteractive lesson
Voltage up, current downInteractive lesson
Transformers waste a littleInteractive lesson
Why the grid uses high voltageInteractive lesson
From power station to plug