Pocket Science Lab - Physics

Shorten the pendulum string — what happens to the period? Double the resistance — how much dimmer is the bulb? Pocket Science Lab answers those "what if" questions as you move a slider, as many times as you like. The graph and the formula move with the experiment, so the numbers and the motion finally line up.

CHANGE A CONDITION, SEE THE ANSWER
Length, mass, starting angle, gravity, spring constant, friction, resistance, refractive index — every experiment has its own sliders, and the scene responds as you drag. Tap a number to type an exact value. Gravity can be set to Earth, the Moon or Mars.

SIX TABS TO CHECK YOUR WORK
• Graph — angle, speed, energy and more, plotted in real time. Drag across it to read any moment.
• Formulas — the textbook equation with your numbers in it, beside the measured value.
• Data — the value at every time step, in a table.
• Challenges — 48 of them, such as "make the period exactly 2.00 s".
• Theory — why it happens, starting from what the symbols mean.
• Predictions — answer first, then check it in the run.

16 EXPERIMENTS
Motion and forces
• Pendulum — length, mass, gravity, period
• Spring pendulum — simple harmonic motion
• Projectile motion — range and peak height
• Incline and friction — when it starts to slide
• Collisions — momentum and energy, before and after
• Circular motion — centripetal force
• Double pendulum — two near-identical runs diverge

Electricity
• DC circuits — current and voltage in your own wiring
• Capacitors — charge, discharge and the time constant τ = RC

Waves and sound
• Damping and resonance — sweep the frequency
• Interference — where two waves add and cancel
• Standing waves — strings and pipes, nodes and antinodes
• Doppler effect — a moving source shifts the frequency

Light
• Refraction and total internal reflection
• Convex and concave lenses — trace three rays

Space
• Planetary orbits — circle, ellipse, escape, Kepler's laws

BUILD THE CIRCUIT YOURSELF
Place batteries, resistors, bulbs, switches, meters and wires on a grid and wire up your own circuit. Series, parallel and bridge presets load in one tap, a bulb glows in proportion to the power it uses, and shorting the battery raises a warning. Trails, force arrows, energy bars and the grid each toggle on their own, and on a tablet the scene and the controls sit side by side.

WHAT PREMIUM ADDS
• 11 more experiments: collisions, circular motion, orbits, double pendulum, resonance, interference, standing waves, Doppler, refraction, lenses and capacitors
• Comparison graphs: overlay quantities and up to 3 previous runs
• XY graphs: plot any two quantities against each other, such as a phase plot
• Data table and CSV export for a spreadsheet
• Records: save conditions and results, reopen them and compare
• Slow motion and frame stepping, ×1/2 down to ×1/10
• Measuring tools: ruler, protractor, stopwatch and light gate
• More presets, and color themes for the app

FREE FOREVER
The five basic experiments — pendulum, spring, projectile motion, incline and friction, DC circuits — come with the sliders, the real-time graph, the formulas with live values, the challenges, the predictions, the theory and image sharing, all free. Nothing inside a free experiment is locked. Premium adds other experiments and other tools.

ABOUT THE PURCHASE
Premium is a one-time purchase: pay once and every extra experiment and tool opens. It is not a subscription. If you change phones, "Restore purchase" brings it back.

IT RUNS ON YOUR DEVICE
All the computation happens on your phone or tablet. No sign-up, no login, no special permissions, and the experiments run in airplane mode. Motion is integrated with Runge-Kutta over small time steps, without shortcuts such as the small-angle approximation — which is why the measured period grows past the textbook formula when you swing wide.

Available in 40 languages, and completely silent.