Students explain static electricity as the transfer of electrons between materials that leaves a charge imbalance, and use it to explain attraction, repulsion and electrostatic discharge (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 10 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 the sound lesson and comes before How does current flow?, which uses the same particle picture inside a wire.
Not a hinge node, but students carry two misconceptions here: that rubbing makes charge, and that protons move. The prediction targets both.
Board notes: eight atoms per material; one electron moves each time Rub is pressed (at most 6). Which material loses electrons depends on the pair; wool to balloon is a typical case. Charging by induction and by contact are left to class demonstrations.
Charge is moved, not made, and only electrons move. When a student says the balloon 'got a positive charge from the wool', ask which particle would have had to cross.
| What you will see | A question to ask | The fix |
|---|---|---|
| A student says the wool and the balloon are both negative. | Where did the balloon's extra electrons come from? | From the wool, which now has fewer electrons than protons, so it is positive. |
| A student says protons moved. | Are protons free to leave the atom? | No: they are locked in the nucleus. Only electrons can be rubbed off. |
| A student thinks a neutral object has no charges at all. | How many + and − are in each atom? | Equal numbers, so they cancel. Neutral means balanced, not empty. |
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.
Open task: any program that does what the step asks.
Stretch: A glass rod rubbed with silk becomes positive and the silk negative. Which material lost electrons? Which gained? (The rod lost; the silk gained.)
Support: Give a two-column table (Before rubbing, After rubbing) with the + and − counts for each material, and let students fill the after column by moving one − at a time.
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 "Where does static charge come from?". 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 the wool and the balloon are both negative. - A student says protons moved. - A student thinks a neutral object has no charges at all. 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 "Where does static charge come from?".
A plastic ruler is rubbed on a cloth and becomes negative. What happened to the cloth, and why?
The cloth became positive. Electrons moved from the cloth to the ruler, so the cloth has more + than −.
Next: How does current flow? uses the same picture inside a metal wire.
In class: rub a balloon on hair and pick up paper bits; a comb or ruler and a thin stream of water; an electroscope or a Van de Graaff generator if available. Many materials charge better in dry air.