Free physics, science and engineering activities for your class

Newton's three laws one at a time: students push objects, add friction and launch, so inertia, F = ma and action-reaction each get their own demonstration.

Push boxes with and without friction, compare F=ma across different masses, and watch elastic collisions demonstrate action-reaction.

Change the hill height and friction, then ride a circular loop and a teardrop loop and compare the g-forces. Potential and kinetic energy trading places, made visible.

Explore potential and kinetic energy, ride tracks to feel g-forces, and compare circle vs clothoid loops.

The build-after: students add a loop or hill to a finished coaster without changing the lift, predict whether the train makes it, then ride it.

Free, no account. Ride a coaster with a loop, watch height turn into speed, then build one of your own.

Students change string length and even gravity (Earth, Moon, Jupiter) and see what sets the period. Then a row of slightly different pendulums makes a wave that is not one.

Discover how pendulums with slightly different lengths drift in and out of sync, creating mesmerizing wave patterns from simple physics.

Launch a body at different speeds and angles and see a crash, an orbit or an escape. Introduces Kepler's laws and why an orbit is falling and missing.

Explore gravitational forces, launch objects into orbit, and discover Kepler's laws through interactive simulations.

Stage a rocket from engines and fuel tanks, watch the delta-v budget, and fly it to orbit. Good for asking why more fuel is not always better.

Free, no account. Start from a rocket and a flight program that reach orbit, pile on more fuel, and watch it fail to leave the pad.

Slide the fulcrum and change the load until the push is easy, then name the three lever classes and the six simple machines.

Adjust fulcrum position and load weight on an interactive lever, explore three lever classes, and discover the six simple machines.

Set tooth counts, add idler gears and build a two-stage train, calculating speed and torque each time. Ends on the torque versus speed trade-off.

How gears multiply force and speed.

A working 3D clock behind glass: wind it, tune the pendulum, break the escapement, and trace how falling weights, gears and cams run it with no motor.

A working 3D cuckoo clock with the case walls turned to glass. Wind it, speed up time, tune the pendulum, break the escapement, and find out how a wooden bird knows to call seven times at seven o'clock.

Push on a square and a triangle, compare beam, truss, arch and suspension bridges, then load a truss until members turn red. Compression and tension, shown with arrows.

Push on triangles vs squares, explore 4 bridge types with force diagrams, and load-test a truss bridge to failure.

Linkages and inverse kinematics from one rule: drag a point, grow it into a chain with joint limits, then solve a two-ended leg with FABRIK one pass at a time.

The whole secret of Creature Lab in five steps. Drag one point and watch another obey a single rule, grow the rule into a chain, stop the kinks, wrap skin around the circles, then solve a leg with FABRIK one pass at a time.

Drag across the spectrum from radio to gamma and watch wavelength shrink as frequency grows, then match each band to a real job.

Click spectrum bands to learn about radio through gamma rays, drag a slider to see wavelength change, and explore real-world uses of each band.

Change the angle and material to see refraction, then move an object and change focal length for convex and concave lenses. Ties optics to cameras, glasses and eyes.

Explore refraction with Snell's law, focus light through convex lenses, spread it with concave lenses, and learn how cameras and telescopes work.

Students change frequency and amplitude, compare AM with FM, and tune across a dial. A concrete way into modulation and a shared spectrum.

The invisible highways carrying your music, texts, and WiFi.

Place a phone and add satellites one at a time until one, two and three distance circles meet at a point. Distance from signal delay, then trilateration.

Click to place your position and watch satellite distance circles converge. See the GPS constellation orbit Earth in real time.

Compress and expand a gas, step through the four-stage refrigeration cycle, flip the reversing valve, and compare a heat pump with a traditional heater.

Discover how heat pumps move heat instead of creating it.

The simplest control loop: set a setpoint and deadband, watch the system cycle with and without a buffer, then plan an away schedule and simulate two weeks.

Discover the clever decision-making loop inside every thermostat.

Students tune P, I and D on a bot driving to a mark and read the response curve to explain overshoot, wobble and stopping short uphill.

Tell a bot to drive somewhere and it misses. Measure how far off it is and feed that number back into the motor, and it does not. Tune the three terms of a real controller, watch the response curve, and find out why every thermostat, drone, and 3D printer runs this exact loop.

Feedback on a real task: a line follower turns one way on dark and the other on white. Students hunt for the turn value that follows most smoothly.

Free, no account. Start from a robot that follows a black line with one light sensor, change one number, and watch it miss the curve.

The overview: split a weight budget between weapon, armor and drive, and see why spinners, wedges and lifters counter each other like rock, paper, scissors.

Explore weapon types with radar charts, compare matchups rock-paper-scissors style, design a weight budget, and learn combat robot engineering principles.

Ram a target and change both weights and the speed. Momentum as mass times speed, and why a heavy bot is harder to knock away.

A ram hits with momentum: mass times speed. Heavy-and-slow can hit as hard as light-and-fast. And the same mass that makes your hit land also keeps you from being thrown. Ram a bot, change the weights, and feel the trade.

Spin up a solid disk and a rim-weighted ring of the same mass and compare the stored energy. Moment of inertia, without the formula first.

Spin up a flywheel, watch it bank energy, and discover why a rim-weighted ring hits twice as hard as a solid disk. The same math runs your BotForge weapon.

An arm as a lever: change arm and body weight, swing a hammer or fire a flipper, and find the point where the bot flips itself.

An arm is a lever. Swing a heavy head fast and a hammer caves a bot in; a flipper trades that damage for a launch that throws light bots clean out of the arena. Swing too big for your body, though, and you flip yourself.

Move a heavy part up and down, widen the wheelbase, and shove the bot. Students predict which build tips before pressing the button.

Find a bot's balance point, then shove it. Discover why heavy parts mounted low and a wide wheelbase make a bot nearly impossible to flip, while a tall top-heavy bot tips on the first hit. The same rule drives the Flip Resistance stat in BotForge.

Where a hit lands decides how much gets through: armor, a wheel or a bare panel. Students add plate and compare how long the bot survives.

Your health scales with weight, and a hit only counts for what reaches the chassis. Armor soaks most of it, a wheel eats some but can break, and a bare panel takes the full blow. Bolt on plate and watch your bot survive twice as long.

Battle-damage a wheeled bot and a tracked bot side by side and find the crossover where staying power beats speed.

Wheels are fast and nimble but fall apart when shot up. Tracks are slow and sluggish but keep driving when half their wheels are gone. Battle-damage two bots side by side and find the crossover where tough beats fast.

Where the labs come together: everyone designs a bot under the same weight limit, predicts how it will do, tests it against AI bots, and changes one thing at a time.

Free, no account. Start from a spinner bot, change the weapon, write the rules it fights by, and take it into the arena.

Pick a hypothesis about whether mass changes fall time, drop objects from 1 kg to 100 kg from the same height, and record each trial. Teaches independent, dependent and controlled variables.

Walk through the scientific method step by step. Form a hypothesis, run a drop experiment, analyze data, and draw conclusions.

Follow water particles through evaporation, condensation, precipitation and collection, change the sun's intensity, and zoom into each stage at the molecular level.

Watch particles evaporate, condense into clouds, precipitate as rain, and collect in the ocean. Adjust sun intensity to speed the cycle.

Students start from a calm day and mix damp air, cold air aloft, lift and turning wind until a storm forms, writing down which ingredient each change added.

Free, no account. Thunderstorms, tornadoes, hurricanes and winter storms, worked out from the same numbers forecasters use.

Bonds, then VSEPR shapes students click through, then water, carbon dioxide, ammonia and methane, ending on why a bent molecule is polar.

Explore atoms, bonds, and molecular shapes. See how VSEPR theory predicts geometry and how polarity determines a molecule's behavior.