🧲 Physics Essentials

What you’ll learn

1. Motion and Newton's LawsDescribe motion using speed, velocity, and acceleration, and explain Newton's three laws with everyday examples.Motion is described by position, velocity, and acceleration. Newton's first law says objects resist changes in motion (inertia), the second says force equals mass times acceleration, and the third says forces come in equal, opposite pairs. These laws explain seatbelts, rockets, and walking. Newton unified earthly and cosmic motion in 1687.
2. Forces and GravityExplain what forces are, how gravity works near Earth and across space, and the roles of friction and circular motion.A force is a push or pull with size and direction. Near Earth gravity accelerates all objects at 9.8 m/s squared regardless of mass. Newton's universal gravitation says every mass attracts every other, weakening with the square of distance. Friction resists sliding, and gravity supplies the centripetal force that keeps satellites and the Moon in orbit.
3. Energy and Its ConservationDefine energy, distinguish kinetic and potential forms, and explain conservation of energy, power, and efficiency.Energy is the capacity to do work, measured in joules, and comes in many forms. Kinetic energy is motion; potential energy is stored. Energy is conserved, only transforming, though friction often turns it into heat. Power is energy per second, measured in watts, and efficiency is the fraction of energy that does the intended job.
4. Waves, Sound, and LightDescribe waves and their properties, and explain sound, light, the electromagnetic spectrum, reflection, refraction, and the Doppler effect.A wave carries energy without carrying material. Sound is a pressure wave needing a medium; light is an electromagnetic wave that crosses a vacuum at 300,000 km/s. Visible light is a thin band of the electromagnetic spectrum. Waves reflect and refract at boundaries, and the Doppler effect shifts frequency for moving sources, revealing cosmic expansion through redshift.
5. Electricity and MagnetismExplain electric charge, current, voltage, resistance, circuits, magnetism, and the electromagnetic link behind motors and generators.Charge comes in positive and negative kinds that attract or repel. Current is flowing charge, voltage is the push, and resistance opposes it, linked by Ohm's law. Circuits can be series or parallel. Electricity and magnetism are one force: currents make magnetic fields and changing fields make currents, which powers motors and generators.
6. Heat and TemperatureDistinguish heat from temperature, describe conduction, convection, and radiation, phase changes, and the second law of thermodynamics.Temperature measures average particle energy; heat is total thermal energy that flows from hot to cold. Heat travels by conduction, convection, and radiation. Adding heat changes states of matter, with temperature holding steady during phase changes. Heat engines turn heat flow into work, limited by the second law, whose rising entropy gives time its direction.
7. The Big Ideas of Modern PhysicsGive an honest tour of special and general relativity and quantum mechanics, and the frontier questions physics has yet to answer.Newton's laws are an excellent approximation but break down at extremes. Special relativity, built on light's constant speed, gives time dilation and E equals m c squared. General relativity reframes gravity as curved spacetime. Quantum mechanics governs particles with quanta, wave-particle duality, and uncertainty. The two great theories are not yet united, marking physics's open frontier.

Questions this course answers

Grounded in trusted sources

• NASA
• Encyclopaedia Britannica
• The Feynman Lectures on Physics (Caltech)
• Royal Institution

Every Wunder lesson is built from real, reputable sources — never invented.

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