This is one of the most important scientific discoveries of all time: moving magnets create electricity. Before this, people thought of electricity and magnetism as two separate things.  When scientists realized that not only were they linked together, but that one causes the other, then the physics really started to fly!

In this lesson, we’re going to take a closer look at how magnets create electricity by building electromagnets, galvanometers, motors, relays, telegraphs, and speakers.  Are you ready?

One of the four fundamental forces of nature, the electromagnetic force is the one that binds atoms together, allows you to walk down the street, and is solely responsible for bad hair days worldwide. One of the greatest leaps in science was the discovery that the electricity and magnetism were a part of each other, and not separate.
By the time you're through with this lesson, you'll have created particle accelerators, galvanometers, curie heat engines, unipolar motors, listened to a magnet (no kidding!), and build a working DC motor. Are you ready? This video will get you started on the right foot for your study into electromagnetism:

You can get started by watching this video, and afterward either read more about it or start your experiments!

Scientific Concepts:

  • Magnetism is caused by moving electrons.
  • Electricity is moving electrons.
  • Electricity causes magnetism.
  • Moving magnetic fields can cause electrons to move.
  • Electricity can be caused by a moving magnetic fields.
  • Electricity is a flow of electrons.
  • A flow of electrons creates a magnetic field.
  • Magnetic fields can cause a flow of electrons.
  • Magnetic fields can cause electricity.

Select a Lesson

Special Science Teleclass: Magnetism
This is a recording of a recent live teleclass I did with thousands of kids from all over the world. I've included it here so you can participate and learn, too! Discover how to detect magnetic fields, learn about the Earth's 8 magnetic poles, and uncover the mysterious link between electricity and magnetism that marks …
Electromagnetic Crane
An electromagnet is a magnet you can turn on and off using electricity. By hooking up a coil of wire up to a battery, you will create an electromagnet. When you disconnect it, it turns back into a coil of wire. Since moving electrons cause a magnetic field, when connecting the two ends of your …
Galvanometers are coils of wire connected to a battery. When current flows through the wire, it creates a magnetic field. Since the wire is bundled up, it multiplies this electromagnetic effect to create a simple electromagnet that you can detect with your compass.
After you’ve completed the galvanometer experiment, try this one! You can wrap wire around an iron core (like a nail), which will intensify the effect and magnetize the nail enough for you to pick up paperclips when it’s hooked up. See how many you can lift! You can wrap the wire around your nail using …
How Generators Work
Have you noticed that stuff sticks to your motor?  If you drag your motor through a pile of paperclips, a few will get stuck to the side. What’s going on? Inside your motor are permanent magnets (red and blue things in the photo) and an electromagnet (the copper thing wrapped around the middle). Normally, you’d …
Quick ‘n’ Easy DC Motor
Find a spare magnet – one you really don’t care about. Bring it up close to another magnet to find where the north and south poles are on the spare magnet. Did you find them? Mark the spots with a pen – put a N for north, and a S for south. Now break the …
Relays & Homemade Shockers
This experiment is for advanced students. If you’ve attempted the relay and telegraph experiment, you already know it’s one of the hardest ones in this unit, as the gap needs to be *just right* in order for it to work. It’s a super-tricky experiment that can leave you frustrated and losing hope that you’ll ever …
Relays and Telegraphs
Relays are telegraphs, and they both are basically “electrical switches”. This means you can turn something on and off without touching it – you can use electricity to switch something else on or off! We’re going to build our own relay that will attract a strip of metal to make our telegraph ‘click’ each time …
Homemade DC Motor
Imagine you have two magnets. Glue one magnet on an imaginary record player (or a ‘lazy susan’ turntable) and hold the other magnet in your hand. What happens when you bring your hand close to the turntable magnet and bring the north sides together? The magnet should repel and move, and since it’s on a …
Hearing Magnetism
Want to hear your magnets? We’re going to use electromagnetism to learn how you can listen to your physics lesson, and you’ll be surprised at how common this principle is in your everyday life. This project is for advanced students. We’re going to invert the ideas used when we created our homemade speakers into a …
Rail Accelerator
We’re going to build on the quick ‘n’ easy DC motor to make a tiny rail accelerator (any larger, and you’ll need a power plant and a firing range and a healthy dose of ethics.) So let’s stick to the physics of what’s going on in this super-cool electromagnetism project. This project is for advanced …