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🎆 Fireworks Shell Burst — Projectile Trajectory & Star Pattern

Interactive fireworks shell simulator. Launch velocity and fuse delay set the burst altitude; star ejection speed and gravity shape the expanding radial burst pattern as it falls, fades and cools.

Explosions & Blast Physics2DEasy60 FPS🔥 Fire

About this simulation

A fireworks shell display is really two stages of classic mechanics stacked together: first ordinary projectile motion carries the shell upward against gravity and drag, then — once its fuse delay elapses — it bursts into dozens of individual "stars" that are each ejected radially and continue as their own small projectiles, falling, spreading and cooling under gravity and drag until they burn out. This simulation lets you shape both stages independently and watch the resulting burst pattern in real time.

🔬 What it shows

A shell climbing under gravity and drag, then bursting into a radial spread of glowing stars that expand, fall and fade exponentially in brightness over their burn lifetime.

🎮 How to use

Set Launch Velocity, Fuse Delay, Star Ejection Speed and Star Count, then click Launch Shell. Watch the burst altitude and maximum burst radius readouts once it detonates.

💡 Did you know?

Because fuse delay directly sets how high the shell has climbed — and therefore how much of its own upward velocity gets added to the stars — a longer fuse produces both a higher burst and a visibly more elongated (rather than perfectly spherical) star pattern in this model.

Frequently asked questions

Why does the shell's ascent slow down before it bursts?

Gravity constantly decelerates the rising shell, and a light drag term further slows it, matching the real, gently curving deceleration of a rising projectile rather than a straight-line rise at constant speed.

Why don't all stars end up at exactly the same distance from the burst point?

Each star is ejected at a randomised speed and angle around the nominal ejection speed, and then follows its own trajectory under gravity and drag — small variations at ejection compound over the burst's lifetime into the familiar organic, slightly irregular burst pattern rather than a perfect geometric sphere.

Why do the stars fade out rather than just stop?

Each star's brightness is modelled as decaying smoothly over its burn lifetime, representing a pyrotechnic star's finite burn duration — real fireworks stars similarly dim and go out once their burning composition is used up.

Does this simulation cover pyrotechnic composition?

No — it only models the kinematics of the shell's flight and the stars' post-burst trajectories and brightness decay; no chemical formulation or construction content is included.

⚙ Under the hood

Simulate a fireworks shell launched into the sky, bursting at its fuse-timed altitude into a radially expanding sphere of glowing stars that fall under gravity and drag while fading and cooling — classic projectile motion and radial-burst kinematics.

Canvas 2Dprojectile motionradial burst patternpyrotechnic kinematics

2D · HTML5 Canvas 2D · 60 FPS target · runs fully client-side, no install