Water freezes, ice melts, and steam condenses. These are ways that water—and all matter—can change. Scientists refer to these changes as changes in state, and they’re all about energy, specifically heat energy.
Matter can transform from one state to another and then back, over and over again. The molecules that compose the matter do not change. A molecule of water still remains H20, whether it has the energy of vapor (a gas), water (a liquid), or ice (a solid).
