and click-drag here to begin.
FALLING SAND
PARTICLE PHYSICS SANDBOX
Created by Tom Wellborn · 2026
TEMPERATURE
The slider is a world thermostat — it sets the ambient environment, not the temperature of materials you place.
Lava is always molten when you place it; a cold world just makes it solidify faster.
Fire always burns hot; a cold world makes it spread less.
Ice is always frozen when placed; a hot world melts it quickly.
Below 32°F water freezes and lava solidifies quickly.
Above 480°F wood and oil spontaneously combust.
Above 2,000°F stone melts back into lava.
Hit INFERNO to instantly jump to 10,000°F plasma — disables the slider until toggled off.
Toggle °F / °C at any time.
Everything not controlled by the UI — atmosphere, pressure, combustion chemistry — assumes Earth standard conditions.
MATERIALS — click a button or press the shortcut key
CONTROLS
Click / drag to paint ·
[ ] brush size ·
C clear ·
Space / P pause ·
H this screen
Ctrl+S save ·
Ctrl+O load ·
Gravity slider — 0 = weightless, high = crushing ·
Speed ¼× – 4× ·
hover any material for live science info
♫ music cycles ambient tracks ·
♪ sfx toggles sound effects (fire crackle, lava bubbling, explosions, zaps, steam)
TRY THESE
Pour water over oil — watch it sink ·
Drop lava into water — instant stone + steam
Hit INFERNO and watch everything vaporise ·
Build an ice wall, pour acid on it
SPACE OR H TO BEGIN ▶
Optimized for larger screens in horizontal mode — phones not supported.