Changing States of Matter

Changing States of Matter

What students learn

Students learn that matter can change state when energy is added or removed. Start with States of Matter: Use Water as an Example because water is easy to see as ice, liquid water, and water vapor.

Why it matters

Changing states explains melting ice, drying puddles, freezing food, foggy mirrors, and boiling water. Use States of Matter Song: Introduce Changing States to introduce the names of common changes.

Learn the idea

When a solid is heated, it may melt into a liquid. When a liquid is heated, it may evaporate or boil into a gas. Cooling can reverse some changes, such as water freezing into ice. Watch States of Matter Song: Liquid Pours and Flows and States of Matter Song: Gas Fills the Space to compare what changes when particles move more freely.

Try it

Draw a three-part water cycle model: ice, liquid water, and water vapor. Add arrows for melting, freezing, evaporation, and condensation. Ask students to write one sentence explaining how heating or cooling causes each arrow.

Parent guide

Point out safe everyday examples: ice melting in a drink, water droplets on a cold glass, or steam from a warm shower. Ask, "Was heat added or removed?" Avoid unsafe boiling demonstrations unless an adult is fully handling the setup.