The Particle Model Simulator

Unit 0 · Skill 0.03 — The particles never change size. Watch what actually changes: the spacing and the motion.

Controls

Particle box

solid

Measurements

Diameter of one particle10 units Average speed (this is temperature)— Total kinetic energy (thermal energy)— Average gap between particles— Wall hits per second (pressure)— Number of particles60 Total mass—

The particle diameter never changes, no matter what you do. Neither does the number of particles or the total mass. Watch the gap and the speed instead.

Heat the ice

solid — ice
Thermometer−20 °C Energy added0 J

Graph: temperature vs. energy added

Press Start heating. Watch the thermometer and the graph at the same time.

Sloped parts: energy makes particles move faster, so the temperature rises. Flat parts: energy is pulling particles apart, so the temperature holds still until the phase change is finished.

Two objects touching

hot: 90 °C
cold: 10 °C
Energy always flows from the hotter object to the colder one, never the other way. They stop when the average speeds match. That is thermal equilibrium.

Temperature vs. time

Hot object thermal energy— Cold object thermal energy— Total thermal energy—

Notice the total never changes. Energy moved; none was made or destroyed. If the cold object is bigger, the final temperature lands closer to the cold one — more particles to share the energy with.

Perfume in a room

How spread out is it?

Time0 s Perfume particles in the far half0 %
Nobody blew the perfume across the room. The particles moved on their own, bouncing off air particles the whole way. Hotter means faster spreading. Gases spread fastest, liquids slower, solids almost not at all.

Check yourself