Earthing simulation
What the Simulation Shows
The simulation depicts a metal object (shown as a sphere) that can be given a negative static charge by adding excess electrons. Here’s what happens at each stage:
Stage 1 – Charging: When you click “Add Charge”, blue particles labelled with a minus sign (−) appear inside the sphere and move around erratically, visually showing that electrons are repelling each other and want to escape. The info box flags this as a warning state.
Stage 2 – Earthing: Clicking “Connect Earth” animates a green wire connecting the object to the ground line at the bottom. The electrons visibly flow down toward the earth, with spark particles travelling along the wire. The object returns to neutral once all electrons have drained away.
Stage 3 – Reset: Clears everything so the cycle can be repeated.
The earth symbol (three horizontal lines of decreasing width) appears at the bottom right as a reference, and the ground line runs across the full width of the screen.
Suggested Classroom Activity
Topic: Earthing and electrostatic safety Level: GCSE Physics (Year 10/11) Duration: ~20–25 minutes Group size: Pairs or threes
Starter (5 min)
Ask the class: “Have you ever got a shock touching a car door or a metal handrail? What do you think caused it?” Take two or three answers, then say: “Today we’re going to find out how earthing prevents that — and why it matters in real industry.”
Main Activity — Guided Exploration (10 min)
Give students this sequence to follow on their own devices (or project it whole-class):
- Click Add Charge once. Observe and sketch what you see. Write one sentence describing where the electrons are and why they’re moving the way they are.
- Click Add Charge again. What changes? Why might more charge make the situation more dangerous?
- Click Connect Earth. Watch carefully. Answer: Where do the electrons go? What does the wire do?
- Click Reset and repeat. This time, try to predict what will happen before each step.
Key questions to discuss in pairs:
- Why do electrons move toward the earth wire rather than staying in the object?
- What would happen if there was no earth connection — where might the electrons go instead?
- Why is earthing important in circuits involving metal appliances like washing machines or kettles?
Extension Task (5 min)
Ask students to write a 3-sentence explanation using these words: electrons, repulsion, earth wire, neutral, potential difference. This works well as a mini whiteboard activity or an exit ticket.
Plenary (5 min)
Return to the simulation whole-class. Ask a student to narrate what’s happening on screen as if they were explaining it to a Year 7 student. Use this as a formative check before moving on to earthing in household wiring or the three-pin plug.
Real-World Links to Mention
- Metal fuel tankers are earthed before unloading to prevent sparks igniting vapour
- Surgeons and electronics technicians wear anti-static wristbands — same principle
- The earth pin in a UK plug is longer than live/neutral so it connects first, earthing the appliance before power flows