Science 7 Notes 10 Phases of Matter Can you describe the phase Melting changes that matter Freezing undergoes? Vaporization Condensation Sublimation 1. Characteristics of a Phase Change What is necessary for a • It’s a change from one state of matter (solid, liquid, gas) to another. phase change to occur? • Phase changes are physical changes because: - It only affects physical appearance, not chemical make-up. What are the states of matter? - They are Reversible 2. What happens during a phase change? During a phase change, heat energy is either absorbed or released. What particle Heat energy is released as molecules slow down and move closer changes are evident when together. heat is added to a substance? Heat energy is absorbed as molecules speed up and expand. 3. Types of Phase Changes What particle changes are A. Melting evident when heat is removed Phase change from a solid to a liquid from a substance? Molecules speed up, move farther apart, and absorb heat energy Describe melting. 1 Science 7 Notes 10 What states of B. Freezing matter change Phase Change from a liquid to a solid during freezing? Molecules slow down, move closer together and release heat energy. How does molecular movement change during freezing? What states of matter change during vaporization? How does molecular movement C. Vaporization/Evaporation change during vaporization? Phase change from a liquid to a gas. Vaporization occurs throughout and happens at the boiling point. Evaporation happens on the surface of a liquid at any temperature. Molecules speed up, move farther apart, and absorb heat energy. 2 Science 7 Notes 10 D. Condensation Phase change from a gas to a liquid. Molecules slow down, move closer together and release heat energy. E. Sublimation Phase change from a solid to a gas. Molecules speed up, move farther apart, and absorb heat energy. F. Deposition Phase change from a gas to a solid. Molecules slow down, move closer together and release heat energy. 3 .