High School Physics: Forces, Energy, Waves, and Circuits by Talking It Through

A taste of a lesson on Newton's second law: F = ma from data

The tutor asks, you answer, and it works from what you actually said. No videos to sit through.

The 23 topics in Physics

Each topic builds on the ones before it. The tutor checks what you already know and starts there.

1. Algebra, graphs, and units for physics

   Review the tools physics uses: solving linear and simple quadratic equations, reading and making graphs of linear relationships, slope as rate of change, proportional reasoning, scientific notation, and SI units with unit conversion and dimensional analysis. Real understanding means a student can rearrange a formula to solve for any variable and check that units make sense.

2. Engineering design process and criteria/constraints

   Introduce the engineering design cycle (define the problem, research, brainstorm, prototype, test, refine). Teach how to analyze a major global challenge and turn it into qualitative and quantitative criteria and constraints that account for societal needs and wants. Teach how to break a complex problem into smaller solvable sub-problems. Students should be able to state criteria and constraints for a real design problem.

3. Evaluating trade-offs and using simulations in design

   Teach how to rank prioritized criteria and weigh trade-offs (cost, safety, reliability, aesthetics, social, cultural, and environmental impact) using a decision matrix. Teach how computer simulations can model how a proposed solution performs under many interacting criteria and constraints, and how to read simulation results critically, including their limits. Students should be able to evaluate a design and justify a choice.

   Builds on Engineering design process and criteria/constraints

4. Motion in one and two dimensions

   Define position, displacement, velocity, speed, and acceleration as vectors versus scalars. Teach the kinematic equations for constant acceleration, reading position-time and velocity-time graphs (slope and area), and projectile motion as independent horizontal and vertical components. Students should solve problems with constant acceleration and explain what a graph shows.

   Builds on Algebra, graphs, and units for physics

5. Forces and Newton's laws of motion

   Teach force as a push or pull, vector addition of forces, net force, free-body diagrams, Newton's first law (inertia and equilibrium), and third law (action-reaction pairs acting on different objects). Students should draw free-body diagrams and identify third-law pairs correctly.

   Builds on Motion in one and two dimensions

6. Newton's second law: F = ma from data

   Teach F_net = ma as the mathematical relationship among net force, mass, and acceleration. Teach how to plan a lab with a cart or track, collect acceleration data for varying force and mass, graph the results (linear with force, inverse with mass in the form a vs 1/m), and use the data to support the claim that the relationship holds. Students should explain how their data support the law, including sources of error.

   Builds on Forces and Newton's laws of motion

7. Momentum and conservation of momentum

   Define momentum p = mv as a vector, impulse as force times time, and the impulse-momentum theorem. State the law of conservation of momentum for a system with no net external force and apply it to collisions and explosions in one dimension using equations. Students should write and solve momentum conservation equations and show total momentum is conserved mathematically.

   Builds on Newton's second law: F = ma from data

8. Collisions, impulse, and designing for safety

   Apply impulse to collisions: increasing the time of impact decreases the average force for the same momentum change (F = Δp/Δt). Teach how crumple zones, airbags, helmets, and padding work through this idea. Students design, build, test, and refine a device, such as an egg-drop container or padded cart bumper, that minimizes peak force in a collision, and explain the physics with evidence.

   Builds on Engineering design process and criteria/constraints, Momentum and conservation of momentum

9. Universal gravitation and Coulomb's law

   Teach Newton's law of universal gravitation F = Gm1m2/r^2 and Coulomb's law F = kq1q2/r^2 as inverse-square laws with the same mathematical form. Students should calculate and predict forces between masses and between charges, compare the strength of gravity and electric force for particles, and explain how changing distance or magnitude changes the force.

   Builds on Newton's second law: F = ma from data

10. Electric current, voltage, resistance, and circuits

    Define electric current as the rate of charge flow (I = Q/t), voltage as energy per unit charge (V), and resistance (R). Teach Ohm's law V = IR, electric power P = IV (and P = I^2R), and series and parallel circuit reasoning. Students should solve circuit problems with current, voltage, resistance, and power and explain how energy is delivered from a source to components.

    Builds on Algebra, graphs, and units for physics

11. Molecular structure and designed materials

    Explain how the molecular-level arrangement of atoms and bonds determines a material's properties (for example, cross-linked polymers vs linear polymers, metallic bonding and ductility, crystalline vs amorphous structure). Students communicate in writing or orally why molecular structure matters to the function of a designed material, such as a flexible plastic, a stronger alloy, or a heat-resistant polymer.

    Builds on Forces and Newton's laws of motion

12. Energy, work, and conservation of energy

    Define work as force times displacement in the direction of force, kinetic energy (½mv²), gravitational potential energy (mgh), and elastic potential energy. Teach the law of conservation of energy and how to write a computational model that calculates the change in one component's energy from the changes in the other components and the energy flowing in or out of the system. Students should solve energy-balance problems and build a simple spreadsheet or code model.

    Builds on Motion in one and two dimensions, Newton's second law: F = ma from data

13. Electric and magnetic interactions and energy

    Teach electric fields and potential energy of charges, how two interacting objects (charges, magnets, current-carrying wires) exert forces on each other, and how work done by these forces changes the energy of each object. Students should build a model showing the force and energy change of two objects interacting through a field.

    Builds on Universal gravitation and Coulomb's law, Electric current, voltage, resistance, and circuits, Energy, work, and conservation of energy

14. Current-magnetism connection and induction investigation

    Teach Oersted's discovery that an electric current produces a magnetic field, and Faraday's and Henry's discovery that a changing magnetic field induces a current (electromagnetic induction). Students plan and conduct a simple investigation (a coil, magnet, galvanometer, or a wire near a compass) that provides evidence for both effects and explain the results with the concept of a field.

    Builds on Electric current, voltage, resistance, and circuits, Electric and magnetic interactions and energy

15. Microscopic energy: kinetic and potential energy of particles and thermal energy

    Teach that macroscopic energy is the sum of kinetic energy of particles (including thermal motion) and potential energy from relative positions of particles (bonds, intermolecular forces). Develop and use models to show how internal energy accounts for the macroscopic energy of an object, including temperature as average particle kinetic energy and phase change as change in potential energy.

    Builds on Energy, work, and conservation of energy

16. Thermal energy transfer and uniform energy distribution

    Teach heat transfer by conduction, convection, and radiation, and the second-law tendency toward uniform energy distribution. Students plan and conduct an investigation (for example, mixing hot and cold water in a closed insulated container) that provides evidence that thermal energy flows from hotter to colder components until temperatures equalize, and they compute the final temperature of a mixture using energy conservation (q = mcΔT).

    Builds on Energy, work, and conservation of energy, Microscopic energy: kinetic and potential energy of particles and thermal energy

17. Designing energy conversion devices

    Teach common energy forms (kinetic, potential, thermal, electrical, chemical, radiant, sound) and how devices convert one into another with efficiency less than 100 percent. Students design, build, and refine a device (for example, a hand-crank generator, a solar-powered motor, or a rubber-band motor) that converts one energy form to another within a given budget, size, or time constraint, and they test and improve it.

    Builds on Engineering design process and criteria/constraints, Current-magnetism connection and induction investigation, Thermal energy transfer and uniform energy distribution

18. Wave properties and the wave equation

    Define wave amplitude, wavelength, frequency, period, and speed, and distinguish transverse from longitudinal waves and mechanical from electromagnetic waves. Teach v = fλ and use it mathematically to relate frequency, wavelength, and speed for waves in different media, such as sound in air versus water or light in air versus glass. Students should compute and explain how speed changes across media.

    Builds on Algebra, graphs, and units for physics

19. Wave behavior: reflection, refraction, diffraction, interference

    Teach how waves reflect, refract (change speed and bend at a boundary, Snell's law qualitatively), diffract around obstacles, and superpose to produce constructive and destructive interference. Students should predict wave behavior at boundaries and in overlapping waves.

    Builds on Wave properties and the wave equation

20. Electromagnetic radiation: wave and particle models

    Describe the electromagnetic spectrum from radio to gamma rays, all traveling at c in vacuum. Teach the photon model (E = hf) and the evidence for both wave behavior (interference, diffraction) and particle behavior (photoelectric effect). Students evaluate the claims and evidence behind the dual models and state when each model is more useful.

    Builds on Energy, work, and conservation of energy, Wave behavior: reflection, refraction, diffraction, interference

21. Frequency effects on matter and evaluating scientific claims

    Teach how different EM frequencies affect matter when absorbed: radio and microwaves cause molecular rotation and heating, infrared causes vibration and thermal effects, visible light causes electronic transitions and color, ultraviolet can break chemical bonds and damage DNA, X-rays and gamma rays ionize atoms. Students evaluate the validity and reliability of claims in published sources (for example, advertisements about sunscreen, Wi-Fi, or radiation safety) using evidence, source quality, and reasoning.

    Builds on Molecular structure and designed materials, Electromagnetic radiation: wave and particle models

22. Digital transmission and storage of information

    Explain how information is encoded as binary, how analog signals are sampled and quantized, and how digital signals resist noise and degradation through error detection and correction. Students evaluate the advantages and trade-offs of digital versus analog transmission and storage, such as bandwidth, copying fidelity, and storage density.

    Builds on Wave properties and the wave equation

23. Wave technologies: transmitting and capturing information and energy

    Explain how antennas, fiber optics, radio receivers, solar cells, microwave ovens, and MRI or ultrasound use wave principles (resonance, reflection, total internal reflection, absorption by matter, photoelectric effect) to transmit or capture information and energy. Students communicate this technical information clearly in a written or oral explanation with diagrams.

    Builds on Wave behavior: reflection, refraction, diffraction, interference, Frequency effects on matter and evaluating scientific claims, Digital transmission and storage of information

Practice questions in Physics

A few of the kinds of questions you will work through, with answers.