Physics 2
About this free Physics 2 course
Physics 2 is a free second-year physics course covering electric circuits and thermodynamics, two core units of AP Physics 2 and algebra-based college physics. Through 20 video lessons, you'll learn how charge flows through circuits and how energy moves as heat.
The circuits half covers electric current, resistance, and electromotive force, using Ohm's law to connect theory to practical applications. You'll solve full DC networks with Kirchhoff's rules and examine power dissipation and energy storage in RC circuits. The thermodynamics half connects the motion of molecules to temperature, pressure, the ideal gas law, and entropy. It's a critical foundation for future studies in engineering, electronics, and the physical sciences.
Who this course is for
The course is for high school juniors and seniors (grades 11-12) who have completed a first physics course, and for students preparing for AP Physics 2. You should be comfortable with Algebra 2 and basic mechanics such as energy and forces.
Course outline
- Current. Electric current, charge carriers, and conventional current direction.
- Simple circuits and resistance. Resistance, resistivity, Ohm's law, and simple circuit diagrams.
- Electrical power. Power in circuits and how devices use electrical energy.
- Direct current circuits. Series and parallel resistors and equivalent resistance.
- Kirchhoff's rules. The junction rule and loop rule for solving multi-loop circuits.
- Resistor-capacitor (RC) circuits. How capacitors charge and discharge, and time constants.
- Kinetic theory. How molecular motion explains temperature and pressure, and the ideal gas law.
- Heat transfer and thermal equilibrium. Specific heat, thermal conductivity, and how systems reach equilibrium.
- Entropy and the second law. Entropy and why heat flows from hot to cold.
What you'll learn
- Apply Ohm's law and power relationships to circuits
- Find equivalent resistance for series and parallel combinations
- Solve multi-loop DC circuits using Kirchhoff's junction and loop rules
- Describe charging and discharging in RC circuits
- Use the ideal gas law and the laws of thermodynamics to explain energy transfer
How long it takes
The video lessons total about 90 minutes. With practice problems, plan on roughly 10 hours to master the material. Circuit analysis rewards working lots of examples.
Frequently asked questions about Physics 2
Is Physics 2 really free?
Yes. Physics 2 is completely free, with no fees, subscriptions, or account required. STEM for Others is a 501(c)(3) nonprofit, and every course in our curriculum library is free for students, families, and teachers.
Does Physics 2 cover AP Physics 2 topics?
It covers the DC circuits and thermodynamics units of AP Physics 2. The course doesn't cover every AP Physics 2 unit, such as optics and modern physics, so pair it with Intro to Optics and official practice exams.
How do I start the course?
Start with the first lesson in the video series on this page, then pause to work through each example yourself. Every lesson is short, so you can fit one into a study break.
Do I get a certificate?
The self-paced Physics 2 materials don't include an official certificate. If you're taking the course through a STEM for Others chapter program, ask your chapter leader about recognizing your completion.
Can teachers and clubs use this curriculum?
Yes. Teachers, homeschool families, libraries, and after-school clubs are welcome to use the Physics 2 materials with their students at no cost. STEM for Others volunteers also teach our curriculum in partner schools and libraries. You can find a chapter near you or start one at your school.
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