States of Matter
States of matter are a foundation of chemistry because they connect what you see to how particles behave. As temperature or pressure changes, matter can melt, freeze, evaporate, condense, or even skip between phases on a diagram. Use the resources below to build intuition, then test those ideas with interactive models and a hands-on lab.
Learning Path
States of Matter
Start with a visual overview of solids, liquids, and gases and how particle spacing changes from one state to another.
Open →Phase Diagram & Heating Curve Explorer
Adjust conditions and see how heating curves and phase diagrams map out melting, boiling, and phase boundaries.
Open →States of Matter Lab
Investigate particle motion, energy, and phase changes in an interactive lab setting.
Open →States of Matter & Phase Changes Cheat Sheet
Keep the core ideas handy while you practice and review.
- Compare the particle spacing, shape, and volume of solids, liquids, and gases.
- Review the energy changes that drive melting, freezing, evaporation, condensation, sublimation, and deposition.
- Use key vocabulary like kinetic energy, boiling point, and phase transition.
More Resources
Tools
Labs
Worksheets
Cheat Sheets
Infographics
Explainers
Common Questions
What causes matter to change state?
Adding or removing heat changes particle energy and motion. Pressure can also shift where a substance sits on its phase diagram.
Why do solids, liquids, and gases behave so differently?
The particles are arranged differently and have different amounts of freedom to move. Intermolecular forces and kinetic energy determine how tightly the particles stay together.