How Does an Electric Current Create a Magnetic Field?

An electric current consists of moving electric charges. When charges flow through a conductor, they generate a magnetic field around it. Coiling the wire concentrates this field, creating a temporary magnet called an electromagnet that attracts magnetic materials.

Medium ⏱ 30-40 min 🔭 Class 6-8 🏠 5 of 7 things are at home 🧑‍🔬 Do it with an adult

Time: 30-40 min
Difficulty: Medium
Best for: Class 6-8
Subject: Physics
Things needed: 7, 5 at home
Steps: 11
Cost: Low, a few things to find
You will learn: Magnetic Effects of Electric Current

How Does an Electric Current Create a Magnetic Field?, Experiment · Class 7 | jijnas.com

Before you start

What you need

0 of 7 ready

Tap each thing once you have it in front of you. Items with the house sign are already somewhere in your home.

🏠 1.5V D-cell or AA battery 1-2 cells No luck? Use standard 1.5V Eveready or Duracell battery from a local kirana shop.
Insulated copper wire (thin plastic coated or enamel winding wire) 1-2 meters No luck? Use connecting wire from a discarded electronic device or thin electrical wire from a local hardware store.
Small magnetic compass 1 unit No luck? Use plotting compass from a school geometry set or lab kit. Alternatively, a mobile compass app can be used to test wire deflection if kept near the wire.
🏠 Iron nail (2-3 inches long) 1 No luck? Use large steel bolt or iron rod from a local hardware shop (lohe ki dukan).
🏠 Small steel paper clips or all-pins 10-15 pieces No luck? Use stapler pins or small iron tacks.
🏠 Insulation tape or cello tape 1 roll No luck? Use black electrical tape or transparent cello tape.
🏠 Sandpaper or small knife 1 piece No luck? Use scissors edge to scrape off wire insulation at the ends.

💬 Send to a parent

Think first

What do you think will happen?

Real scientists guess before they look. Write one line now. After the steps, the page will show it next to what you should see.

Safety first, an adult should be with you.

Connecting insulated wire directly across battery terminals creates a short circuit, which will rapidly heat up the wire and battery. Only complete the circuit for brief 2-3 second bursts to prevent burns, thermal injuries, or battery overheating.
Be cautious with the sharp point of the iron nail and stripped wire ends.

Do it

The procedure

Tap a step when it is done. Lab mode shows one step at a time in big letters, reads it aloud if you want, and keeps the timer.

Place the magnetic compass on a stable, flat surface and wait for the needle to point north.
Strip 1/2 inch of plastic insulation off both ends of a 30 cm copper wire using sandpaper or a knife edge.Carefully scrape the wire ends away from your body to prevent accidental cuts.
Lay the center portion of the wire directly over top of the compass, aligning it parallel to the settled needle.
Secure one bare end of the wire to the positive terminal of the 1.5V battery using tape.
Press the free bare end of the wire against the negative terminal for just 2 seconds while watching the compass needle.Do not hold the wire against the battery for more than 3 seconds, as the direct short circuit will rapidly heat the wire and battery.
Release the wire end immediately to break the circuit and note how the needle returns to its original position.
Swap the wire ends on the battery terminals to reverse the electric current, then briefly touch the connection again to observe the opposite deflection.Keep contact brief (2-3 seconds maximum) to avoid thermal burns or battery failure.
Wind a long piece of insulated copper wire tightly around a large iron nail in a single continuous direction, leaving 5 cm of loose wire at each end.Mind the sharp point of the iron nail while tightly coiling the wire.
Tape one stripped end of the coiled wire to a battery terminal.
Touch the remaining wire end to the free battery terminal while bringing the tip of the nail near a pile of paper clips.Limit this connection to short bursts of 2-3 seconds to prevent excessive heat build-up in your hands.
Disconnect the wire from the terminal to watch the nail drop the paper clips as the magnetic field collapses.

01 · The idea

The Concept

Electricity and magnetism were long thought to be completely separate forces. In 1820, Hans Christian Oersted noticed a compass needle move when an electric current was switched on nearby. This experiment lets you recreate that discovery and build your own temporary electromagnet.

02 · What you should see

Observation

Here is what you will observe during both parts of the experiment:

Oersted Experiment: As soon as you complete the circuit, the compass needle twitches and turns away from its north-south alignment. The moment you disconnect the wire, the needle swings back to pointing north.
Reversing Current: If you swap the wire connections on the battery terminals, the compass needle deflects in the opposite direction.
Electromagnet Demonstration: When current flows through the wire wrapped around the iron nail, the nail becomes magnetized and lifts small paper clips. Disconnecting the battery instantly drops the paper clips as the nail loses its magnetism.

03 · Why it happens

Why It Happens

When electric charges sit still inside a material, they only produce an electric force. However, as soon as those charges begin to move through a wire to form an electric current, their motion creates an invisible magnetic field around the wire.

Think of a speedboat moving across a calm lake. When the boat sits still, the water remains flat. But as soon as the boat zooms forward, it creates ripples and waves that push against nearby floating objects. In a similar way, moving electric charges create magnetic ripples in space that push against the magnetic needle of a compass.

When you wrap the wire around an iron nail, every single loop of wire adds its magnetic ripples together, turning the nail into a temporary magnet.

04 · The science

The Science Behind It

This fundamental phenomenon was discovered by Danish scientist Hans Christian Oersted in 1820. He proved that electricity and magnetism are closely linked, forming the foundation of electromagnetism studied in NCERT physics chapters on the magnetic effects of electric current.

Here are the key scientific principles involved:

Magnetic Field Direction: An electric current produces circular magnetic field lines around a straight wire. Changing the direction of current flips the direction of these field lines, which is why reversing the battery connections reverses compass needle deflection.
Strengthening the Field: A single wire produces a weak magnetic field. Coiling the wire into multiple turns combines the field lines of each loop, creating a strong solenoid field similar to that of a bar magnet.
Ferromagnetic Core: The soft iron nail acts as a magnetic core. When exposed to the magnetic field of the wire coil, tiny magnetic regions inside the iron align, dramatically amplifying the overall magnetic pull.
Temporary Electromagnetism: Electromagnets are non-permanent magnets. Stopping the electric current removes the magnetizing force, causing the core to lose its magnetic strength almost instantly.

05 · Take it further

Make It a Project

Turn this demonstration into a full science fair project by testing how different factors change the strength of the magnetic field:

Variables to Test: Change the number of turns around the nail (20, 40, or 60 turns) or add a second battery in series to see how voltage affects magnetic strength. Measure how many paper clips the electromagnet can lift in each trial.
Data Collection: Create a table logging coil turns versus paper clips lifted. Run three trials for each variation and calculate the average.
Presentation Tip: Display your results using a simple bar graph. Draw clear diagrams showing the circular magnetic field lines around a straight wire and the concentrated magnetic field around a coil.
Advanced Challenge: Test different core materials (such as aluminum, plastic, or a steel bolt) to show how core permeability affects an electromagnet. You can also use a magnetometer smartphone app to measure field intensity in microteslas.

06 · Questions students ask

FAQs

Why does the compass needle move when the circuit is switched on?

The compass needle is a small magnet that points toward Earth's magnetic north. When electric current flows through the wire next to it, the current generates its own magnetic field. This new field pushes against the compass needle, causing it to rotate away from north.

Why does an iron nail make the electromagnet stronger than just coiled wire?

Iron is a ferromagnetic material containing tiny magnetic domains. When you wrap a live wire around the nail, the wire's magnetic field aligns all these domains inside the iron. This temporarily turns the nail into a magnet, making the overall magnetic force much stronger.

What happens to the magnetic field if you reverse the battery terminals?

Reversing the battery terminals flips the direction of the electric current flowing through the wire. Because the direction of a magnetic field depends on the direction of the current, the magnetic field flips too. This causes the compass needle to deflect in the opposite direction.

How can you increase the strength of an electromagnet?

You can make an electromagnet stronger in three simple ways: wrap more loops of wire around your iron core, increase the electric current by adding another battery cell, or use a soft iron core instead of materials like steel or plastic.

Why does the iron nail stop attracting paper clips when you disconnect the battery?

The magnetic field is created by the movement of electric charges. When you disconnect the battery, the electric current stops immediately. Without moving charges to maintain the field, the tiny magnetic domains inside the soft iron nail randomize again, losing their magnetic pull.

Write it up

Your lab notebook

Two minutes here and your lab record is done. Everything stays on this device until you copy it out.

Did it work?

What I actually saw What I would change next time

💼 Same science, as a real job

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