States of matter
Drag the temperature. Watch the particles. Discover when matter changes state.
01 Choose a substance
Pure substances at approximately 1 atmosphere (101.3 kPa). Transition temperatures are rounded for this learning model.
02 From substance to particles
What you see
Enlarged particle view
Motion is slowed down and exaggerated to make it visible.
The linked views are schematic, not to scale. The circle marks the region being examined; magnification is illustrative. Circles represent whole molecules for water, carbon dioxide, iodine and oxygen, and atoms for iron. Their size and number stay the same during a change of state. The box is a viewing region, not a sealed fixed-volume vessel. Colours in the particle view identify substances; they are not the colours of individual particles.
Heating within one state increases particles’ average kinetic energy. During a change of state at constant pressure, energy changes particle interactions while the temperature stays constant.
Model and data sources
This is a qualitative equilibrium model: no supercooling, chemical reactions or decomposition are simulated. Evaporation rates are omitted. A selected gas state means the vapour of the original substance in this model.
Reference data: NIST: water · NIST: carbon dioxide · RSC: oxygen · RSC: iron · RSC: iodine.