demonstrations:rope_loop_electric_circuit

Rope Loop Electric Circuit

Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required

Categories: Electricity

Alternative titles: Modeling Electricity with a Rope

Summary

A rope loop passed around a circle of students models how electric circuits work. The teacher moving the rope represents the battery, while a student gripping the rope models a resistor or bulb. This activity helps students visualize current, energy transfer, and resistance in circuits.

Procedure

  1. Arrange students in a large circle, either in a hall or outdoors.
  2. Hand out a rope loop (6–9 mm thick) so it rests lightly on each student’s curled fingers.
  3. Begin moving the rope continuously around the circle to represent current flow.
  4. Instruct one student to grip the rope more tightly while it moves, creating resistance (like a bulb).
  5. Ask students to observe how the rope keeps moving everywhere at once, but energy is transferred where resistance occurs.
  6. Use guided questions to connect the model to electric circuits (e.g., battery makes charges move, current is same everywhere, energy shifts at resistors).

The Rope Loop Model (and how it Explains AC) - GCSE and A Level Physics - Physics Online:


📄 From rope loop to electric circuit model - Institute of Physics: https://spark.iop.org/rope-loop-electric-circuit-model

Variations

  • Use multiple “resistors” (students gripping rope) to show how energy is shared across different components.
  • Compare rope speed with different numbers of students pulling to illustrate more or less current.
  • Try using two rope loops in parallel paths to demonstrate parallel circuits.

Safety Precautions

  • Ensure students handle the rope gently to avoid rope burns.
  • Use a rope of safe thickness (not too thin or rough).
  • Supervise in large open spaces to prevent tripping hazards.

Questions to Consider

  • Where does the “rope” (charge) come from? (It is already in the circuit; the battery just sets it moving.)
  • Does the current get used up? (No, it is the same everywhere in the loop.)
  • Why does the student gripping the rope feel warming? (Friction resists the rope’s movement, like resistance in a circuit transferring energy.)
  • What happens when the rope starts moving? (All parts of the rope move at once, just as current flows instantly around a complete circuit.)
  • How does this model help explain why larger circuits work the same way as smaller ones? (The rope moves as a loop regardless of its length, showing current flows everywhere in the circuit.)