There’s a reason for that.
Go from “I saw it happen” to “I know why” with twelve connected explanations.
Start with movement
From a moving dot to an energy exchange.
Find the pattern
Connect repeated motion to waves.
Explore the invisible
Follow current through wires and light through lenses.
Physics concepts, one idea at a time
Projectile motion
Projectile motion separates into constant horizontal velocity and vertical acceleration.
Position, velocity & acceleration
Velocity is the rate of change of position, and acceleration is the rate of change of velocity.
Force & friction
Static friction adjusts to oppose a push, up to μsN.
Energy on a ramp
Gravity transfers energy from potential to kinetic form as height decreases.
Pendulum explorer
For small angles, the restoring force gives approximately simple harmonic motion.
Spring oscillator
The spring force points toward equilibrium and grows with displacement.
Traveling wave explorer
A wave carries a disturbance.
Ohm’s law & power
Voltage provides an electrical potential difference.
Series & parallel resistors
Series components share a current, and their voltage drops add to the supply.
Refraction & total internal reflection
Light changes direction when it crosses between media with different refractive indices at oblique incidence.
Converging lens explorer
The thin-lens equation relates focal length to object and image distance.
Buoyancy & floating
A fluid exerts an upward buoyant force equal to the weight of displaced fluid.