• Quick retrieval from earlier learning (Melting, freezing, evaporating and condensing). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Which change of state is this: water in an ice-cube tray in the freezer? (melting / freezing / evaporating / condensing) → freezingPrompt: What state does it start in, and what state does it end in?
2. What is the name for a change from solid to liquid? (evaporating (or boiling) / melting / freezing / condensing) → meltingPrompt: Heating makes solids melt and liquids evaporate.
3. Changes of state: which statement is true? (The water on the outside of a cold can leaks through the metal. / Cooling can make a gas condense into a liquid. / Water only evaporates when it boils. / Melting makes a substance lose mass.) → Cooling can make a gas condense into a liquid.Prompt: Where does the water on a cold can come from?

• Show an ice cube melting and a kettle steaming and ask what is the same and what is different.
• Share the objective: What makes water evaporate faster?. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: In a fair test of whether wind speeds up drying, what must stay the same?
• Step 1: Keep everything else the same so only the wind can explain the difference.
• Step 2: So the answer is: the amount of water, the cloth and the temperature
• Answer: the amount of water, the cloth and the temperature
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. Why does washing dry slowly on a cold, damp, still day? (Damp air is too light. / Cold makes water heavier. / Clothes like being wet. / Cold, still, damp air slows evaporation.) → Cold, still, damp air slows evaporation.Prompt: Which three things speed drying?
2. True or false? Spreading water out makes it evaporate faster. (True / False) → TruePrompt: Warmth, wind and surface area: what does each do?

• Students work on the student sheet. Circulate and check the first two answers of every student early.
• Students who finish: write a question of their own for a partner, with the answer.

The 8 questions are on the student sheet below, with answers in the key.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. True or false? Evaporated water is destroyed. (True / False) → FalsePrompt: Warmth, wind and surface area: what does each do?
2. In a fair test of whether wind speeds up drying, what must stay the same? (only the colour of the pegs / the amount of water, the cloth and the temperature / nothing / the wind) → the amount of water, the cloth and the temperaturePrompt: Change only the wind.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-4.