Course I · Open courseware
AP Physics 2: Algebra-Based
7 units · 27 chapters · free
09
Thermodynamics
4 chapters- 01Molecules in a Box: Temperature, Pressure, and the Ideal Gas LawA tire's pressure is nothing but trillions of tiny collisions per second, and its temperature is how hard each one hits. Count the collisions and the gas law falls out.
- 02Heat: Thermal Equilibrium, Specific Heat, and ConductionA metal bench and a wooden bench sit at the same temperature all night, yet at dawn only the metal one feels cold. Your hand measures flow, not temperature.In preparation
- 03The First Law of Thermodynamics and PV DiagramsSqueeze a gas quickly and it gets hot with no flame anywhere. The piston did work, and the gas has nowhere to keep that energy except in the speed of its molecules.
- 04Entropy and the Second LawEvery collision in a gas is perfectly reversible, yet a broken egg never reassembles. The arrow of time is hiding in a counting argument, not in the collisions.
10
Electric Force, Field, and Potential
4 chapters- 05Charge, Charging, and Coulomb's LawRub a balloon on your hair and it clings to a wall that carries no net charge at all. Charge is never created, only moved, and the force between charges is like gravity but enormously stronger.
- 06The Electric FieldA charge sitting alone in empty space feels a push before it can know what pushed it. The space itself has been changed, and that change has a name and an arrow.
- 07Electric Potential Energy, Potential, and the Energy of a Moving ChargePush two like charges together and you can let go with nothing moving, yet the energy you spent has not vanished. It is stored in the arrangement, and a map of it predicts every motion.
- 08CapacitorsTwo metal plates a hair apart, and suddenly a circuit can store energy like a spring. Slide a sheet of plastic between them and it stores even more.
11
Electric Circuits
4 chapters- 09Current, Resistance, and Ohm's LawFlip a switch and the light is on instantly, yet the electrons in the wire crawl slower than a snail. What moves fast is not the charge but the push.
- 10Electric Power and Compound CircuitsAdd a second bulb in parallel and the first one does not dim at all; add it in series and both go dim. Which bulb is brightest is a question about power, not current alone.
- 11Kirchhoff's RulesTwo batteries and three resistors, and no amount of series-or-parallel bookkeeping will untangle it. Two conservation laws will — one for energy, one for charge.
- 12Capacitors in CircuitsClose the switch and the capacitor behaves like a plain wire; wait, and it behaves like a broken one. Everything interesting about the circuit happens in between.
12
Magnetism and Electromagnetism
3 chapters- 13Magnetic Fields and the Force on a Moving ChargeCut a bar magnet in half and you get two complete magnets, never a lone north. And the field it makes pushes a moving charge sideways — never forward, never back.In preparation
- 14Magnetism from CurrentsRun a current through a wire and a compass beside it swings. Run a second current nearby and the two wires pull on each other with no magnet anywhere in sight.
- 15Electromagnetic Induction and Faraday's LawHold a magnet still inside a coil and nothing happens; move it and a current appears from nowhere. It is not the field that makes current, but the change.
13
Geometric Optics
3 chapters- 16Reflection and Images in MirrorsYour reflection in a flat mirror stands exactly as far behind the glass as you stand in front, in a place no light ever reaches. Curve the mirror and that image can move, flip, and grow.
- 17Refraction and Total Internal ReflectionA straw in a glass of water looks broken at the surface, and a fish sees the whole sky squeezed into a circle overhead. Light changes speed at the boundary, and bending is the cost.
- 18Images Formed by LensesA magnifying glass makes a page look larger, then, held farther away, turns the room upside down. One curved piece of glass, one equation, and two very different images.
14
Waves, Sound, and Physical Optics
5 chapters- 19Waves, Sound, and the Doppler EffectA wave on a rope carries energy from one end to the other while every piece of rope stays home. Sound does the same through air, and a passing siren proves that motion changes what you hear.In preparation
- 20Boundaries, Polarization, and Light as a WaveA pulse hitting a fixed end comes back upside down; hitting a free end it comes back upright. Light passing two crossed polarizing filters does not come through at all — and that tells you what light is.In preparation
- 21Superposition, Beats, and Standing WavesTwo waves can pass straight through each other and come out unchanged, yet while they overlap they can cancel to nothing. A guitar string is that cancellation frozen in place.In preparation
- 22Diffraction and Double-Slit InterferenceShine light through two narrow slits and the screen shows stripes, with dark bands where two lights add up to darkness. Young settled a century-old argument with that one picture.In preparation
- 23Thin-Film InterferenceA soap bubble has no color of its own, yet it shimmers in every color, and the top of it turns black just before it pops. Two reflections, a hair's-width apart, are interfering.In preparation
15
Modern Physics
4 chapters- 24Light Comes in Lumps: Blackbody Radiation and the Photoelectric EffectA hot poker glows red, then orange, then white, and a dim ultraviolet lamp kicks electrons out of a metal that a blinding red floodlight cannot touch. Neither fact makes sense if light is only a wave.In preparation
- 25Photons, Compton Scattering, and Matter WavesFire X-rays at electrons and they bounce off like billiard balls, losing exactly the energy and momentum a particle would. Then de Broglie asked the reverse question: if light is a particle, is an electron a wave?In preparation
- 26The Bohr Atom and SpectraHeat hydrogen and it glows in a few sharp colors and no others, the same colors every time. An orbit that must hold a whole number of electron wavelengths explains every line.In preparation
- 27The Nucleus: Radioactive Decay, Fission, and FusionA nucleus weighs less than the protons and neutrons that make it, and that missing mass is the energy holding it together. Release a little of it and you have a star, or a bomb.In preparation