Simulation Description: Electrostatic Field Strength Explorer
This simulation is a visual lab instrument for understanding the inverse square law in electrostatics.
At the centre is a draggable electric charge. Around it, a glowing heatmap field radiates outward, showing how electric field strength changes with distance. The area closest to the charge burns bright red-orange (extremely strong), fading smoothly through yellow and green into deep blue as distance increases.
This makes the key idea instantly visible:
Field strength decreases rapidly as distance increases (E ∝ 1/r²).
Over the heatmap are concentric dashed rings representing equipotential contours — circles where the field strength is the same. The rings are tightly packed near the charge and spread further apart as you move away, reinforcing how quickly the field weakens.
A movable probe tool allows learners to measure field strength anywhere on the canvas:
- Shows distance (r)
- Displays a scaled arrow showing field direction and strength
- Gives a live percentage of maximum field
- Updates a plain-English explanation of what 1/r² means at that position
Dragging the charge instantly recalculates the entire field in real time, reinforcing that the field belongs to the charge — not the space.
The overall aesthetic feels like a scientific instrument panel, helping learners think like physicists rather than just observers.
Suggested Class Activities
1. Guided Discovery: “What Do You Notice?”
Objective: Identify the relationship between distance and field strength.
Ask students:
- Where is the field strongest?
- How does colour change as you move away?
- Why are rings closer together near the charge?
- If you double the distance, does the field halve?
Let them move the probe and record:
| Distance (r) | Field Strength (E) | Pattern Observed |
|---|
Then guide them to notice:
If r doubles → E becomes one quarter.
2. Predict & Test Challenge
Objective: Apply the inverse square law.
Give students a scenario:
If the probe reads 100% at 1 unit away, what should it read at:
- 2 units?
- 3 units?
- 4 units?
They predict first.
Then test using the probe.
This builds conceptual confidence before formal equations.
3. SEND-Friendly Concept Building
For learners who struggle with abstract maths:
- Turn off numbers.
- Focus only on colour and arrow size.
- Ask: “Is it stronger here or here?”
- Physically move the probe slowly outward.
This builds intuitive understanding before symbolic reasoning.
4. Drag & Re-centre Activity
Move the charge to different parts of the screen.
Ask:
- Does the field strength pattern change?
- Or does it just move with the charge?
This reinforces that:
The field depends on the charge, not the background space.
5. GCSE / A-Level Extension Task
Have students:
- Measure E at 1, 2, 3, 4 units.
- Plot a quick graph of E vs r.
- Then plot E vs 1/r².
They will see the second graph forms a straight line — proving the inverse square relationship.