• Quick retrieval from earlier learning (Series and parallel circuits). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Two lamps are in series with a 12 V battery. The voltage across one lamp is 1 V. What is the voltage across the other lamp, in V? → 11 VPrompt: In series, the battery voltage is shared between the components.
2. In a series circuit, the current is… (the same at every point / biggest after the bulb / zero at the battery / used up by each component) → the same at every pointPrompt: There is only one path for the charge.
3. Series and parallel: which statement is NOT true? (In series, total resistance is the sum of the resistances. / In a series circuit, if one bulb breaks, the others go out. / Ammeters are connected in parallel. / In a parallel circuit, the voltage across each branch is the same.) → Ammeters are connected in parallel.Prompt: Is current used up in a circuit?

• Show a circuit with a gap and ask why the bulb doesn't light.
• Share the objective: Current and voltage rules in series and parallel circuits. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Two lamps are connected in series to a 12 V battery. The voltage across the first lamp is 8 V. What is the voltage across the second lamp, in V?
• Step 1: 12 − 8 = 4
• Step 2: So the answer is: 4 V
• Answer: 4 V
• 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. Two lamps are connected in series to a 4.5 V battery. The voltage across the first lamp is 2.25 V. What is the voltage across the second lamp, in V? → 2.25 VPrompt: In series, the supply voltage is shared between components.
2. A 0.9 A current leaves a battery and splits into two parallel branches. One branch carries 0.8 A. What current flows in the other branch, in A? → 0.1 APrompt: Current is not used up; it is shared between branches.

• 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. An ammeter reads 0.4 A before the first lamp in a series circuit. What will it read after the last lamp? (more than 0.4 A / less than 0.4 A / 0 A / 0.4 A) → 0.4 APrompt: A series circuit has just one loop.
2. Two lamps are in parallel. The current through one branch is 1 A and through the other is 0.4 A. What current flows from the battery, in A? → 1.4 APrompt: In parallel, the current splits between branches.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-8.