Students do not arrive as blank slates. They arrive with years of wrong intuitions. Here is how to use simulation to replace them.
A physics misconception is not an absence of knowledge — it is an actively held wrong model that students apply consistently and confidently. Telling a student they are wrong rarely dislodges the misconception. They need to experience the contradiction directly, at a moment when they are invested in their prediction being right.
Simulation is particularly effective for this because it provides instant, parametric, repeatable contradiction. If a student predicts that the heavier ball falls faster, you can run the simulation ten times with different masses in ten seconds. The evidence is unambiguous and immediate.
The oldest misconception in physics. Drop two balls of different masses in PHYSIX with air resistance = 0. They hit the ground at exactly the same time. Then add air resistance and watch a feather fall more slowly — helping students distinguish between mass effects and drag effects.
Students confuse velocity with force. In PHYSIX, give a ball an initial velocity in empty space with no forces active. It travels in a straight line forever. Ask: "What force is keeping it moving?" The correct answer — none — contradicts the intuition that motion requires a cause.
"Centrifugal force" is not a real force in an inertial reference frame. Set up a circular orbit and remove the centripetal force mid-orbit. The ball travels in a straight line tangent to the circle — not outward. The outward sensation is inertia, not a force.
Kepler's First Law: orbits are ellipses with the Sun at one focus. Build an elliptical orbit in PHYSIX and measure the distance from the Sun to the nearest and furthest points — they are clearly different. Students are often surprised the Sun is not at the geometric centre.
Students think satellites "escape" gravity. In fact, they are in constant free fall — they just keep missing the Earth because they are moving sideways fast enough. PHYSIX's Newton's cannon preset makes this viscerally clear.
Momentum is always conserved; kinetic energy is not (unless perfectly elastic). Newton's Cradle with restitution = 0.8 shows energy decreasing across swings while momentum is conserved. Use the energy graph to make the loss visible.
Students expect a louder (higher amplitude) pendulum to swing faster. Build a pendulum in PHYSIX and vary the amplitude while measuring the period. Period is independent of amplitude for small angles — this is genuinely surprising to most students and takes several trials to believe.
Friction opposes relative motion between surfaces. When you walk, the friction force on your foot from the ground is forward, in the direction of motion. This is unintuitive. PHYSIX's rolling bodies with friction show the correct direction of the friction vector.
Field lines show the direction a positive test charge would accelerate — not the path it would actually travel. A charge released from rest does follow the field line, but a charge with initial velocity perpendicular to the field takes a curved path that does not follow the lines.
Sound and water waves transport energy, not matter. The water in a wave moves up and down — it does not travel with the wave. Use the wave source tool to show individual particles oscillating in place while the wave pattern propagates forward.
Discussion
Questions, corrections, and insights welcome.