States of matter – particle model on heating and cooling

Integrated ScienceMatter & MaterialsAges 11–12

In a solid, particles sit close together and only vibrate; in a liquid they slide past each other; in a gas they move freely. Click Heat or Cool, or drag the temperature slider, to watch the substance melt, boil, condense, and freeze; the temperature-vs-time graph flattens at the melting point and the boiling point. Choose water, ethanol, mercury, or oxygen to compare.