Unit 1 Lesson 6 Changes of State Copyright © Houghton Mifflin Harcourt Publishing Company

The Fact of the Matter What happens when matter changes state? Unit 1 Lesson 6 Changes of State The Fact of the Matter What happens when matter changes state? The three most familiar states of matter are solid, liquid, and gas. A change of state is the change of a substance from one physical form of matter to another. When a substance undergoes a physical change, it does not change its identity, just its appearance. Copyright © Houghton Mifflin Harcourt Publishing Company

What happens when matter changes state? Unit 1 Lesson 6 Changes of State What happens when matter changes state? To change a substance from one state to another, energy must be added or removed. When a substance gains or loses energy, its temperature changes or its state changes. Copyright © Houghton Mifflin Harcourt Publishing Company

What happens when matter changes state? Unit 1 Lesson 6 Changes of State What happens when matter changes state? All matter is made of tiny particles that are in constant motion. During a change of state, the motion of the particles changes. Particles can break away from each other and gain more freedom to move, or they may attract each other more strongly and have less freedom to move. During a change of state, a substance gains energy from or loses energy to the environment, but the total amount of energy is conserved. Copyright © Houghton Mifflin Harcourt Publishing Company

What happens when matter changes state? Unit 1 Lesson 6 Changes of State What happens when matter changes state? Where in this diagram do water particles gain energy from the environment? Where do they lose energy? Copyright © Houghton Mifflin Harcourt Publishing Company

Solid Facts How do solids and liquids change state? Unit 1 Lesson 6 Changes of State Solid Facts How do solids and liquids change state? The change in state in which a liquid becomes a solid is called freezing. When a liquid is cooled, its particles have less energy, they slow down, and they lock into the fixed arrangement of a solid. The temperature at which a liquid substance changes into a solid is the liquid’s freezing point. Copyright © Houghton Mifflin Harcourt Publishing Company

How do solids and liquids change state? Unit 1 Lesson 6 Changes of State How do solids and liquids change state? When a solid is warmed, its particles gain energy and speed up, and the attraction between them decreases. Eventually they slide past one another. The change of state from a solid to a liquid is called melting. The temperature at which a substance changes from a solid to a liquid is called its melting point. Copyright © Houghton Mifflin Harcourt Publishing Company

Bubbling Over How do liquids and gases change state? Unit 1 Lesson 6 Changes of State Bubbling Over How do liquids and gases change state? As a liquid is warmed, its particles gain energy. Some particles gain enough energy that they escape from the surface of the liquid and become a gas. This process is called evaporation. Copyright © Houghton Mifflin Harcourt Publishing Company

How do liquids and gases change state? Unit 1 Lesson 6 Changes of State How do liquids and gases change state? A rapid change from a liquid to a gas, or vapor, is called boiling. This change takes place throughout a liquid, not just at the surface. The specific temperature at which this occurs in a liquid is called the boiling point. Copyright © Houghton Mifflin Harcourt Publishing Company

How do liquids and gases change state? Unit 1 Lesson 6 Changes of State How do liquids and gases change state? How does evaporation differ from boiling? Which of these processes is represented here? Copyright © Houghton Mifflin Harcourt Publishing Company

How do liquids and gases change state? Unit 1 Lesson 6 Changes of State How do liquids and gases change state? As a gas is cooled, its particles lose energy. The attraction between particles overcomes the speed of their motion, and a liquid forms. This change of state from a gas to a liquid is called condensation. Copyright © Houghton Mifflin Harcourt Publishing Company

How do liquids and gases change state? Unit 1 Lesson 6 Changes of State How do liquids and gases change state? What is happening to the water particles in each image? Copyright © Houghton Mifflin Harcourt Publishing Company

Into Thin Air How do solids and gases change state? Unit 1 Lesson 6 Changes of State Into Thin Air How do solids and gases change state? Under the right conditions, some solids and gases can change state without ever becoming a liquid. The change from a solid state directly into a gas is called sublimation. Deposition is the change in state from a gas directly to a solid. Copyright © Houghton Mifflin Harcourt Publishing Company

Conserve What happens to matter when a change of state occurs? Unit 1 Lesson 6 Changes of State Conserve What happens to matter when a change of state occurs? When matter changes from one state to another, its physical state changes but its chemical identity does not. During a change of state, the energy of the particles, their movement, and the distance between them change. Copyright © Houghton Mifflin Harcourt Publishing Company

What happens to matter when a change of state occurs? Unit 1 Lesson 6 Changes of State What happens to matter when a change of state occurs? The mass of a substance does not change when its state changes. Each state contains the same amount of matter. Copyright © Houghton Mifflin Harcourt Publishing Company