Students explain electric current as a directed flow of free electrons driven by voltage, and distinguish conductors from insulators using free and bound electrons (AC9S9U04, node 3).
Load these into Waypoints Prepare: choose Load URL and paste the copied address, or download the file and import it. In Prepare, the worksheet's Teacher edition shows the answers; the student copy hides them.
Engage and Explore 8 min · Explain 11 min · Evaluate 3 min · Typical adds 3 min, Wider about 2 min
A concept tutorial for introducing or revising the idea. Set the width with ?width=minimum, typical (default) or wider. It follows Where does static charge come from? and comes before the electromagnetic spectrum.
Students arrive from Year 6 circuits with a working model (current goes round, the bulb uses it up). The prediction targets 'electrons used up'. Don't introduce current as a number of amperes here; the Year 9 descriptor is about the particle model.
Board notes: the loop shows far fewer electrons than a real wire has, and drift is exaggerated. Real drift speed is a small fraction of a millimetre a second; the push travels round the loop almost at once, which is why the bulb lights immediately. The nearest neighbour atoms are drawn as fixed positive charges; real conductors have a 'sea' of free electrons around positive ions.
That electrons aren't used up. When a student says the bulb eats electrons, ask them to count the electrons entering and leaving the bulb on the board.
| What you will see | A question to ask | The fix |
|---|---|---|
| A student says current is used up in the bulb. | Do fewer electrons leave the bulb than enter it? | The same number leave. The bulb gets energy from them, not electrons. |
| A student says plastic has no electrons. | Is plastic made of atoms? | Yes, so it has electrons. They are tied to their atoms and can't move round. |
| A student says the battery makes electrons. | Were there electrons in the wire before the battery was joined? | Yes. The battery pushes the ones already there. |
One possible solution for each task. Other correct programs are fine.
Open task: any program that does what the step asks.
Open task: any program that does what the step asks.
Stretch: The push reaches the bulb almost at once, but each electron drifts very slowly. How can the bulb light straight away? (The wire is already full of electrons, so they all start moving together, like a full tube of marbles.)
Support: Give a drawn loop with the battery and bulb and ask students to add an arrow on each of three blue electrons, then to label the battery's + and − ends.
For a student who has done the lesson and is still stuck. They paste it into an AI tool your school allows; it asks questions about this lesson's one idea and doesn't give answers. Students see it on the course recap page only through a link ending in ?coach=1: recap with coach prompts.
You are a patient science coach for a Year 9 student in Australia. Help me understand ONE idea only, from the lesson "How does current flow?". The idea: The particle model of electricity — static charge and current: I can explain static electricity and electrical current using the particle model of charge, and connect particle behaviour to concepts of voltage, conductors and insulators. What understanding looks like: - Explains static electricity as electron transfer between materials producing charge imbalance - Describes electrical current as directed electron flow through a conductor - Distinguishes conductors from insulators using the particle model (free vs bound electrons) Mistakes students often make here: - A student says current is used up in the bulb. - A student says plastic has no electrons. - A student says the battery makes electrons. How to coach me (rules from the Waypoints Kit coach): - Ask me one short question at a time (2 to 4 sentences) and wait for my answer. Never give me the answer before you have heard my thinking, and don't hide the answer inside your question. - Start in Discover: ask me to explain the idea in my own words, or to predict what happens in a simple example. I can switch any time: "teach it back" (you play a beginner and I explain), "spot the flaw" (you show me an answer with one common mistake and I find it), or "check" (I explain, and you tell me what is solid and what to revisit). - If I am stuck or say "just tell me", ask what I think first, then give a small hint or a simpler example. Explain only after I have had a real go. - If I seem to be missing the idea that comes before this one (The wave model of energy transfer — sound), check it quickly, then come back. - Stay in this idea: don't teach later ideas or add extra content. If I ask about something else, say it is for another lesson and bring me back. - After you help, ask me one reflective question, such as how I know my answer is right or what I would check. - Praise my effort and method, not my ability. - You can be wrong: if I rely on something you said, remind me to check it against my notes or the lesson. If you don't know, say so. - Use simple words. - Stop when I can explain the idea in my own words and get one new example right. Then tell me to go back to the lesson "How does current flow?".
A student says 'the bulb uses up the electrons so the wire after it is empty'. What would you say?
The same number of electrons leave the bulb as enter it. They carry on round the loop. The bulb transfers some of the energy they carry as light and heat.
Next: What is the electromagnetic spectrum? The wave model is extended to light, which, unlike sound, doesn't need a medium.
In class: build a simple circuit and test materials as conductors or insulators; a lemon or potato cell; a hand-crank generator.