• 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: wet washing drying on a line? (melting / freezing / evaporating / condensing) → evaporatingPrompt: What state does it start in, and what state does it end in?
2. What is the name for a change from liquid to solid? (freezing / evaporating (or boiling) / condensing / melting) → freezingPrompt: Heating makes solids melt and liquids evaporate.
3. Changes of state: which statement is true? (Water evaporates faster on a warm, windy day. / The water on the outside of a cold can leaks through the metal. / Water only evaporates when it boils. / Melting makes a substance lose mass.) → Water evaporates faster on a warm, windy day.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: Temperatures of water changing state. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Water in a pan starts at 23 °C. By how many degrees must it warm up to reach its boiling point?
• Step 1: 100 − 23 = 77
• Step 2: So the answer is: 77 °C
• Answer: 77 °C
• 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. Water in a cup is at 21 °C. By how many degrees must it cool to reach its freezing point? → 21 °CPrompt: At what temperature does water freeze?
2. Why do people put salt on icy roads in winter? (Salt soaks up the water / Salt water freezes at a lower temperature than pure water / Salt is heavier than ice / Salt makes the road hotter) → Salt water freezes at a lower temperature than pure waterPrompt: Salt dissolves in the thin layer of water on the ice.

• 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. At what temperature does pure water boil at sea level? (50 °C / 0 °C / 100 °C / 212 °C) → 100 °CPrompt: Water boils at 212 °F, but what is that in °C?
2. Water in a pan starts at 21 °C. By how many degrees must it warm up to reach its boiling point? → 79 °CPrompt: At what temperature does water boil?

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-3.