--- title: "States of matter for kids: a melting and freezing lesson" description: "A 45-minute states of matter lesson: freeze, melt and steam on the whiteboard, then an ice-cube race for real. Fits Year 4 and NGSS 2-PS1-1." source_name: "Game Tailors" source_url: "https://extreemtekenen.nl/en/for-teachers/states-of-matter/" site_home: "https://extreemtekenen.nl/" source_description: "The drawing app where the paper is real. No ads, no accounts, no data collected." locale: "en" legal: - "Game Tailors · Schieweg 15Y-40, 2627 AN Delft (NL)" - "KvK 92437702 · VAT NL866044474B01" - "info@gametailors.com · +31 6 4227 5919" copyright: "© 2026 Game Tailors" published_at: "2026-10-24T00:48:11.570Z" modified_at: "2026-10-24T01:17:56.837Z" --- # States of matter for kids: a melting and freezing lesson ## Solid, liquid, gas, and back again Most materials can be a solid, a liquid or a gas, depending on how warm they are. In this 45-minute lesson pupils freeze a painting solid, melt ice cream and chocolate and watch wet paper steam dry on the whiteboard, then race ice cubes for real and measure the temperatures. [Play in your browser]()[Jump to the lesson plan](<#plan>) - 45 minutes - Year 4 · Grades 2 to 5 - Free tools only ![Painted illustration of the painter pointing a pencil at a melting ice cube, beside melting chocolate and a kettle letting off steam.]() ## At a glance Age 7 to 10 \(England Year 4; US grades 2 to 5; NL groep 5 to 7\) Fits KS2 Year 4 states of matter · NGSS 2-PS1-1, 5-PS1-1 · kerndoel 42 Time 45 minutes In the app \(all free\) Paint, Ice cream, Chocolate, Ice cube, Pour water, Iron, Hammer, Put in the freezer, Bake in the oven For real Ice cubes, saucers, thermometers, a timer, a glass of iced water, chocolate squares on foil Teacher only Anything hot. Pupils never handle a kettle or hot water ## Learning objective and standards **Objective:** pupils can sort materials into solids, liquids and gases, and describe how heating or cooling changes a material from one state to another. **Success criteria** - I can say whether something is a solid, a liquid or a gas, and why. - I can name melting, freezing and evaporating. - I can measure the temperature where ice melts, and compare places that melt it faster. [NGSS 2-PS1-1]()[England science programmes of study]() ### Where it fits - **England, Year 4, States of matter:** compare and group materials as solids, liquids or gases; observe that some materials change state when heated or cooled, and measure or research the temperature in °C; the part evaporation plays, and how its rate depends on temperature. - **NGSS 2-PS1-1:** classify materials by their observable properties \(many kinds of matter can be either solid or liquid, depending on temperature\). - **NGSS 5-PS1-1:** a model of matter made of particles too small to see \(evaporation is one of its examples\). - **Netherlands, kerndoel 42:** investigating materials and physical phenomena such as temperature. ![Painted illustration of the painter pointing a pencil at a melting ice cube, beside melting chocolate and a kettle letting off steam.]() ## What the app shows - **Solids:** a bar of **Chocolate** is hard and snaps under the **Hammer**. After **Put in the freezer**, every puddle, sauce and patch of wet paint is frozen solid, and frozen paint shatters into icy chips when you hit it. - **Liquids:** an **Ice cream** scoop melts at room temperature, edges first \(thin parts warm through faster\), and runs into a puddle. Chocolate warmed with the **Iron** goes glossy and runny, then sets again about 20 seconds after the heat goes. - **Gases:** run the **Iron** over wet paper and it dries with puffs of steam and a hiss. After **Bake in the oven** steam rises off the hot food. Vinegar on baking soda fizzes up into a foam full of gas. - **Evaporation:** wet paper dries slowly on its own and much faster next to heat. The **Ice cube** freezes just the spot you hold it on; a warm finger melts a print into the frost. [Play in your browser]() ## The lesson, step by step Set up before the lesson: the browser version open on the board, ice cubes in a cool box, a thermometer and saucer per group, and a glass of iced water on your desk from the start \(it needs time to fog up\). 1. 5 minutesHook: freeze a paintingLet a pupil paint a big wet blob with **Paint** and pour a puddle with **Pour water**. Tap **Put in the freezer**, then hit the frozen paint with the **Hammer**. It shatters. Ask: *was the paint a solid or a liquid before? And now?* 2. 5 minutesPredictShow an **Ice cream** scoop, a bar of **Chocolate** and a patch of wet paper. Pairs predict: which will melt by itself in the room? Which needs heat? What will we see when the iron touches wet paper? 3. 10 minutesTry it on the boardWatch the ice cream melt \(about a minute and a half for a whole scoop; the edges go first\). Melt the chocolate with the **Iron**, lift it off and count until it sets. Run the iron over the wet paper: puffs of steam, a hiss, dry paper. Name each change as it happens: melting, setting, evaporating. 4. 15 minutesDo it for real: the ice-cube raceEach group puts an ice cube on a saucer in a different place \(on the desk, by the window, in a cupped hand on a paper towel, next to a radiator\). Measure the temperature at each spot, start the timer and record which melts first. Meanwhile, look at the iced glass on your desk: where did the water on the outside come from? 5. 10 minutesExplainPool the results: warmer spots melt faster. Draw the three states on the board with arrows: melting, freezing, evaporating, condensing. Explain that the white cloud above a kettle is tiny water droplets; the water vapour itself is invisible. Exit question: *is chocolate a solid or a liquid?* \(Both, depending on how warm it is.\) Safety - Keep radiators and windows only warm, never hot; no hot water, kettles or hair dryers at pupil tables. - Ice straight from the freezer can stick to skin: hold it on a paper towel. - If you use chocolate, check allergies \(milk, soya, nuts\) and follow your school's rules on eating in science. - Mop up meltwater straight away so nobody slips. ## Vocabulary and differentiation **Key words** - **solid**: keeps its own shape - **liquid**: flows and takes the shape of its container - **gas**: spreads out to fill any space; often invisible - **melting / freezing**: solid to liquid, liquid to solid - **evaporating**: liquid to gas, faster when warm - **condensing**: gas to liquid, on something cold - **temperature**: how hot or cold something is, measured in °C Support ### Sort the board Pupils come up and point: solid, liquid or gas? Use picture cards for the real versions. Grade 2 pupils can stop at sorting by what they observe. Core ### Measure and compare A results table for the ice-cube race \(place, temperature, minutes to melt\), and one sentence: *the warmer it was, the…* Stretch ### Tricky materials In the app, ketchup holds a little bead and only runs when the blob gets tall enough. Is ketchup a solid or a liquid? What about the foam from vinegar and baking soda, which is a liquid full of gas? What are the three states of matter? Solid, liquid and gas. A solid keeps its shape, a liquid flows and takes the shape of its container, and a gas spreads out to fill whatever space it's in. Is steam a gas? Water vapour is a gas, and it's invisible. The white cloud you see above a kettle is tiny drops of water that have condensed again as the vapour cools. Why do the edges of an ice cream melt first? Thin parts warm through faster than the thick middle. You can see it in the app and on a real cone. What is a fun states of matter experiment for kids? An ice-cube race: put ice cubes in different places, measure the temperature at each and time which melts first. It needs only ice, saucers and a thermometer. ## Next lessons and experiments ![Painted illustration of two sheets of paper, one covered in frost ferns from the freezer and one baked golden from the oven, the painter holding an ice cube and an oven glove.]() ### [Reversible and irreversible changes]() Freezer against oven: which changes can you undo? ![Painted illustration of the painter pouring red vinegar onto a heap of baking soda on a tray, which fizzes up into pink foam.]() ### [Baking soda and vinegar]() A fizz full of gas: carbon dioxide you can see as foam. ![Painted illustration of a cola bottle on the grass shooting up a tall fountain of foam as mints drop in, the painter in goggles laughing beside it.]() ### [Cola and mints]() The gas hiding in a drink, all coming out at once. ## Freeze the paint, then race the ice Free in the browser, no pupil accounts. More lessons and the curriculum map are on the teachers' page. [Play in your browser]()[All lessons and the curriculum map]()