Back-to-School Beginner Science Experiments about Electricity Part 4 - The Kitchen Radio

Back-to-School Beginner Science Experiments about Electricity Part 3 – Magnetic Attraction

Electricity seems like pretty magical stuff — subatomic force particles found in practically everything. The scientific term for these particles is “electrons,” and for the most part, the technology behind controlling them is very basic. “How basic?” you might ask. So basic that you can show your child how it all works from inside your home. With our Back-to-School Beginner Science Experiments about Electricity series, you and your kids will utilize similar materials and techniques used by Edison, Tesla, and other pioneers of electric energy when they began their experiments over a century ago.

Back-to-School Beginner Science Experiments about Electricity Part 3 - Magnetic Attraction
Remember – Only conduct these experiments with proper adult supervision.

Hello again! We’re glad you’ve returned for yet another science experiment you can do at home to teach your kids about electricity. This week, it’s all about the principles of magnetic attraction.

So once again, let’s take a look at our basics:

While most of the materials you’ll need are probably already in your home, for this experiment you will need a few important things you can easily find in your local home improvement store.

Back-to-School Beginner Science Experiments about Electricity Part 3 - Magnetic Attraction
An example of alligator test leads.
  • A Pair of Alligator Test Leads – These are wires with little clips at the ends that let you connect circuits.
  • A 6-Volt Lantern Battery – These put out a good, safe level of power.
  • A Red LED Light – LED stands for “Light Emitting Diode”. You’ll want one of these and NOT a red LED light bulb.
  • Enameled/lacquer-coated Copper Wire – This wire is used for making coils and has a thin coating of insulation.

While you won’t be needing to solder any connections in these circuits, you will need to double check that your connections are conducting electricity through them.

PLEASE NOTE: None of these circuits or their components are designed to be plugged into household wall sockets or use household current. They are too weak for that level of power and connecting them to household current is extremely dangerous.

It’s Time to Get Attractive with Magnets and Coils

When electricity moves through a wire, it creates an electromagnetic field all around the wire. Wrapping the wire into a coil increases the electromagnetic field’s strength. When you place an iron (or steel) rod into a coil, you drastically increase the electromagnetic power of that field.

That’s what an electromagnet is. Turn on the power, and it can pick up amazingly huge loads of steel and iron. Turn it off, and the stuff falls. Making one is easy — all you need is a 1/4 inch diameter steel bolt, some tape, your lantern battery, lacquer-insulated copper wire, and a bit of patience.

Back-to-School Beginner Science Experiments about Electricity Part 3 - Magnetic Attraction
L to R: masking tape, lacquer-coated copper wire, test leads, a steel bolt, lantern battery, and paper clips

Here’s How It Works

Back-to-School Beginner Science Experiments about Electricity Part 3 - Magnetic Attraction
Winding the copper wire firmly around the bolt for 120 turns. I used a piece of 3/8″ steel rod so you can see the copper wire winding easier. Please don’t tell my wife that I sanded off the lacquer with one of her nail emery boards.

1) Allow one inch to hang loose and wind the wire firmly around the bolt for 120 turns. Use a little masking tape to hold it in place.

2) For the field to work set up properly, the wire must be insulated and unbroken. If it breaks, you have to begin winding all over again. Use a little tape to hold the last of the 120 turns in place and let the last 1 inch of wire to hang loose.

3) Sand off half an inch of lacquer insulation from each end of the copper wire.

4) Connect each of the stripped wire ends onto one of your battery test leads.

Back-to-School Beginner Science Experiments about Electricity Part 3 - Magnetic Attraction
Here’s the completed magnet circuit. The red test lead clips to one end of the coil to the battery, while the black lead clips to the other end of the coil to the other battery terminal.

5) Have your child hold the coiled bolt over a pile of paper clips.

6) Connect the battery leads to the lantern battery. Voila! It picks them up.

7) Disconnect one of battery wires and the magnet drops the paper clips.

8) The more windings your coil has, the more powerful the electromagnet becomes.

Back-to-School Beginner Science Experiments about Electricity Part 3 - Magnetic Attraction
Electrical resistance in the magnetic coil can get quite warm so only keep the circuit connected for about a minute.

What can you do with it?

Coils and magnets make all kinds of things —electric motors, dynamos (generators), and electric switches (“solenoids”).

  • Coils of fine copper wire wrapped thousands of times around permanent magnets are used as pickups on electric guitars.
  • Coils that move in and out of magnets are used as speakers and microphones for the bands using those electric guitars.
  • Coils by themselves also limit frequency fluctuations. Called “chokes,” they can be tuned to block out or isolate certain frequencies. For example, if you have radio noise messing up your cable TV connection, making a simple little choke could eliminate it.

I hope you had as much fun building that magnet as I did! What else gets you charged up about electricity? Let us and your fellow readers know in the comments!

By the Way…

You can check out Part One about the lemon battery and Part Two about making a resistor with a pencil for more science goodness!

If you’ve had fun with these experiments, there are hundreds more you and your child can do together to learn even more about electricity. Two classic books that go into better detail about how electricity works are:

  1. Getting Started in Electronicsby Forest M. Mims III
  2. 100 Amazing Make-It-Yourself Science Fair Projects by Glen Vecchione.

Do you have any beginner science experiments you’d like to share with our readers? Tell us about them in the comments!

Next Week: We’ll build a homemade radio in Part 4.

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