technifyed
Weekly list
Opportunities
Learn
ProjectsPrepareAI toolsGet the weekly list

Popular: InternshipsScholarshipsFree coursesInterview prep

Physics · Electromagnetism

Electromagnetic braking in a copper pipe

Time a magnet falling through copper, aluminium and plastic pipes and show how eddy currents slow it.

  • DifficultyIntermediate
  • Estimated time2–7 days
  • Budget₹250–₹500
  • ClassClass 10–12
  • TeamSolo or up to 3
  • You needHousehold materials

Prerequisites: Magnetic field, Faraday's law in words, speed = distance ÷ time

Original · by TechnifyedScience Fair ProjectWorking ModelLow costWell documented

My projects

Overview

A magnet dropped through a conducting pipe falls far more slowly than through a plastic one. The moving field induces currents in the metal, and by Lenz's law those currents oppose the motion. Timing the fall through different pipes shows the effect clearly.

Why build this?

It is one of the most striking demonstrations of electromagnetic induction, and the same effect brakes trains and roller coasters.

What you will learn

  • How a changing magnetic field induces a current
  • What Lenz's law predicts about direction
  • Why conductivity changes the braking force
  • How terminal velocity appears when forces balance

Skills you will use

Controlled comparisonGraphingTiming

Safety

  • This project uses a blade or sharp tool. Cut away from your body on a cutting mat, and ask an adult to help younger students.

Materials and tools

  • Neodymium disc magnets (2 or 3)
  • Copper pipe about 50 cm long
  • Aluminium pipe and PVC pipe of the same length and bore
  • Non-magnetic object of the same size (steel-free)
  • Stopwatch or phone camera

Tools and software

Phone slow-motion cameraStopwatch

Expected cost₹250–₹500About ₹450 at most, less if you borrow parts
Estimated duration2–7 days6 build steps, plus the report

Make it cheaper: Roll thick aluminium foil into a tight multi-layer tube instead of buying metal pipe.

Step-by-step roadmap

  1. Start

    You will finish with: a table and chart of fall times for each pipe, with an explanation using Lenz's law.

  2. 1

    Prerequisites

    Know this first: magnetic field, Faraday's law in words, speed = distance ÷ time. Then collect the 5 items in the materials list.

  3. 2

    Learn

    • How a changing magnetic field induces a current
    • What Lenz's law predicts about direction
    • Why conductivity changes the braking force
    • How terminal velocity appears when forces balance
  4. 3

    Plan

    Sketch the design, list every part with its price and decide how you will know it works.

  5. 4

    Build

    1. Check that the magnet slides freely in each pipe without touching the sides hard.
    2. Hold a pipe upright over a cushion and drop the non-magnetic object through; time the fall five times.
    3. Drop the magnet through the PVC pipe and time it five times.
    4. Repeat with the aluminium pipe, then the copper pipe.
    5. Stack two magnets and repeat with the copper pipe.
    6. Work out the average speed in each case and plot a bar chart.
  6. 5

    Test

    The magnet should take several times longer in copper than in PVC, while the non-magnetic object shows no difference.

  7. 6

    Document

    Photograph each build stage, keep the circuit or drawing, and note what failed and how you fixed it. Report structure

  8. 7

    Present

    Demonstrate it working first, then explain how it works and what you would improve. Presentation structure · Viva questions

  9. 8

    Publish

    Share a short video, the parts list and the drawing or code so someone else can build it.

Expected outcome

A table and chart of fall times for each pipe, with an explanation using Lenz's law.

Other versions of this project

Beginner version

Compare only the copper pipe and the plastic pipe and describe the difference.

Advanced version

Film the magnet leaving the pipe in slow motion and show it has reached a steady terminal speed; compare pipes of different wall thickness.

Research version

Cut a slit along a copper pipe and measure how much the braking falls; relate the result to the path of the eddy currents.

Low-budget version

Roll thick aluminium foil into a tight multi-layer tube instead of buying metal pipe.

Make this project better

  1. BasicCompare only the copper pipe and the plastic pipe and describe the difference.
  2. This projectElectromagnetic braking in a copper pipe
  3. AdvancedFilm the magnet leaving the pipe in slow motion and show it has reached a steady terminal speed; compare pipes of different wall thickness.
  4. ResearchCut a slit along a copper pipe and measure how much the braking falls; relate the result to the path of the eddy currents.

Ways to do this project

Text marked "You write this" is a prompt for your own work; everything else is specific to this project.

Problem
How does the conductivity of a pipe affect the time a magnet takes to fall through it?
Hypothesis
If the pipe conducts better, then the induced currents are larger and the magnet falls more slowly.
Variables
Independent: pipe material. Dependent: fall time. Controlled: pipe length and bore, magnet, drop height

Materials and procedure are in Materials and the Roadmap.

Observation table

PipeTrial 1–5 (s)Mean time (s)Mean speed (m/s)
Graph
Bar chart of mean fall time against pipe material
Results
You write thisState what the graph shows in one or two sentences, with numbers.
Conclusion
You write thisSay whether the result supports your hypothesis and why you think so.

Display board

  • Title and your name
  • Question
  • Hypothesis
  • Materials
  • Procedure (with photos)
  • Data table and graph
  • Conclusion
  • What you would do next

Questions judges ask

  • Why does the magnet not stop completely?
  • Why is copper better than aluminium?
  • Would an iron pipe work?
  • What would you change if you did this again?
  • What was your biggest source of error, and how did you reduce it?
  • Where is this idea used in real life?

Working as a team

Solo or up to 3. Suggested roles:

DesignHardware and buildCode or controlTestingDocumentationPresentation

Report and presentation

Report structure

  1. Title and aim
  2. The problem it solves
  3. How it works (principle)
  4. Parts list with cost
  5. Design: drawing, circuit or block diagram
  6. Build steps
  7. Testing and results
  8. Problems faced and fixes
  9. Limitations
  10. Future improvements
  11. References

Presentation structure

  1. The problem
  2. The idea
  3. How it works (one diagram)
  4. Parts and cost
  5. The build (photos)
  6. Live demo or video
  7. Test results
  8. What did not work
  9. Next version

Viva questions

Try answering before you open each one.

Why does the magnet not stop completely?

The braking force exists only while the magnet moves; if it stopped, the induced current would vanish and it would fall again.

Why is copper better than aluminium?

Copper has higher conductivity, so larger eddy currents flow.

Would an iron pipe work?

The magnet would stick to it, so the comparison would not be fair.

Where is this used?

Eddy-current brakes on trains, roller coasters and in electricity meters.

Resources

PhET interactive simulationsphet.colorado.eduNCERT textbooksncert.nic.in

Source and attribution

Original

Written by Technifyed. Free to use for your own school or college project; write the report in your own words. Added 1 Oct 2026.

Similar projects

More Physics projects

Physics · Dynamics

Launch a water rocket and predict its range

Build a bottle rocket and find the water volume and angle that give the longest flight.

  • Intermediate
  • 2–7 days
  • 250–500
Working Model · Household materialsView

Same tools

Industrial and Manufacturing + Operations, HR and Supply Chain

Analyse and reduce waiting time at the canteen

Time each step of the canteen queue, find the bottleneck and test one improvement.

  • Intermediate
  • 1–2 weeks
  • Free
Field Study · No equipmentView

Public Health and Epidemiology · Healthcare Management

Study how a hospital or clinic manages its queue

With permission, time each stage of an outpatient visit and suggest how to cut waiting.

  • Intermediate
  • 1–2 weeks
  • Free
Field Study · No equipmentView

Sports and Exercise Science + Physics

Analyse a sports technique with video

Film a bowling action, a jump or a throw in slow motion and measure the joint angles and speed.

  • Intermediate
  • 1–2 weeks
  • Free
Data Analysis · A phoneView

Two-subject alternatives

Electrical Engineering + Physics

Build a wireless power transfer demo

Light an LED with no wire connection using two coils and an oscillator.

  • Intermediate
  • 2–7 days
  • 250–500
Working Model · Basic electronicsView

Aerospace Engineering + Physics

Make a model wind tunnel and test shapes

Build a small wind tunnel from a fan and straws and compare the drag of different shapes.

  • Intermediate
  • 1–2 weeks
  • 500–1,000
Engineering Design · Household materialsView

Same difficulty and budget

Biology · Microbiology

Grow bacteria from everyday surfaces

Swab phones, door handles and washed hands onto agar and compare the colonies that grow.

  • Intermediate
  • 2–7 days
  • 250–500
Experiment · Lab equipment requiredView

Earth Science + Data

Map earthquakes from live data

Download a month of world earthquakes and show that they trace the plate boundaries.

  • Intermediate
  • 2–7 days
  • Free
Data Analysis · Computer onlyView

Earth Science · Seismology

Build a seismograph and record vibrations

Make a pen-and-weight seismograph that draws a trace when the table shakes.

  • Intermediate
  • 2–7 days
  • Under 250
Working Model · Household materialsView

Astronomy and Space + Aerospace Engineering

Design a Mars habitat and justify every choice

Design a base for four astronauts and explain how it provides air, water, food, power and radiation shielding.

  • Intermediate
  • 1–2 weeks
  • Under 250
Engineering Design · Household materialsView

Enter your email and the official page opens. Phone is optional.

We email you a code to confirm the address. We save your email, and your phone number if you add it, to send you this link and, if you tick the box, the weekly list. Under 18? Ask a parent or guardian first. How your details are used.

Open official page