Primary Science

Exploring Electromagnets: A Fascinating World of Magnetism and Electricity!

Hey there, curious minds! Have you ever wondered how some things around us magically attract and repel without any visible strings attached? Let’s unravel this mystery together and discover the captivating world of electromagnets!

magnet-shock-screw-battery

Imagine this:

You have a magical wand that can turn ordinary objects into magnets just by switching it on. That’s the power of an electromagnet! But how does it work?

An electromagnet is a special kind of magnet that can be turned on and off using electricity. It’s like having a superhero magnet that obeys your commands. How does it become so powerful? It’s all about the science of electricity and magnetism teaming up!

DIY Science: Make a Magnet - National Science Week
Photo taken from National Science Week

Firstly, let’s gather our materials:

  • Coil of Wire: Take a long piece of wire and wrap it around an iron nail. This creates a coil, like a spring made of wire.
  • Battery: Grab a battery, the one that powers your toys, remote control, or flashlight.
  • Magnetic metal: Find something made of any magnetic material, like steel paper clips.

 

The four magnetic materials are:

Superman- Steel

Is – Iron

Not – Nickel

Cool – Cobalt

(Take note that copper is non-magnetic. Cobalt is the magnetic material, not copper!)

cobalt-copper-magnetic-nonmagnetic

Now, let’s put this superhero team together! Connect the ends of the wire coil to the positive and negative sides of the battery. Electric current flows through the wire coil, and something incredible happens.

The nail has been magnetised into an electromagnet, thanks to the electric current flowing through it.

Place the electromagnet near magnetic materials, and whoosh! They are attracted to your electromagnet just like magic. Remove the power source, and voilà! The magnetism disappears. Isn’t that amazing?

But why does this happen? It’s all because of the invisible force called magnetism. When electricity flows through the wire coil, it creates a magnetic field around it. This magnetic field is what attracts the metal objects, turning your nail into a temporary magnet.

invisible-magnetic-field-wire

You might wonder, “Where do we find electromagnets in our daily lives?”

Well, they’re all around us! From our fridges, to the doorbells that chime when someone’s at your door, to the super cool maglev trains that float above their tracks— electromagnets make it all possible. Ever noticed those gigantic cranes at construction sites lifting heavy loads effortlessly? Yep, electromagnets help them too!

scrap-yard-chime-doorbell-maglev-train-magnet

 

In a chime doorbell,

there is an iron core attached to a non-magnetic bar. When there is no electrical current flowing through the electromagnet, a spring pushes the piston to the left.

When you press the doorbell, electric current flows through the electromagnet, magnetising it and the iron core is attracted to electromagnet.

As the iron core slides to the right, the end of the piston strikes the tone bar. The tone bar vibrates, producing a note. This is the “ding” sound.

As long as you hold the doorbell button, electric current will flow through the electromagnet and the piston will remain in this position. But when you release the button, the electrical current will stop flowing through the electromagnet and becomes demagnetised. The spring snaps the piston back to the left, where it hits the tone bar on the other side. The second tone bar produces the “dong” sound.

A blender,

also has an electromagnet inside it with a permanent magnet surrounding the electromagnet. When you plug the blender into an electrical outlet and turn it on, the electricity flows through the cord, inside the blender base, and to the electromagnet.

When the electromagnet comes in contact with electricity, it reacts with the permanent magnet that surrounds it. The electromagnet ends up spinning and turning the blender’s blades along with it!

blender-black

Even inside a fridge,

electromagnets are used. A compressor is like the heart of the fridge because it helps to keep things cold. And inside the compressor, there is a special part called a motor.

fridge-motor-compressor

Inside the fridge’s motor, there are coils of wire. When electricity flows through these coils, it is magnetised into an electromagnet, creating a magnetic field. This magnetic field helps the motor do its job of compressing a special gas called refrigerant.

Here’s how it works:

  • The compressor’s motor has these coils of wire.
  • When electricity flows through these coils, it creates a magnetic field, which makes the motor’s parts move.
  • As the motor moves, it compresses the refrigerant gas (e.g. Freon gas).
  • When the gas gets compressed, it becomes really hot. But don’t worry! The fridge has something called condenser coils that help cool down the hot gas.
  • As the gas cools down, it turns back into a liquid.
  • This liquid then moves through the fridge, absorbing heat from inside and making everything nice and cold.
  • The liquid goes back to the compressor, and the whole process starts again.

So, electromagnets in the motor help make the compressor work, and that’s how a fridge keeps your food cold!

But this would be useless without a door. So, the fridge also has magnetic door seals to keep the door closed tightly.

The door of the fridge has a rubber gasket embedded with a magnetic strip. When the door is closed, the magnetic strip attracts the metal frame of the refrigerator, creating an airtight seal that helps maintain the internal temperature and prevents cold air from escaping.

magnet-escape

Remember, the next time you see a magnet in action, think about the amazing teamwork between electricity and magnetism that brings these wonders to life. Keep exploring, keep discovering, and who knows what fantastic creations you’ll unlock with the power of electromagnets!

Read More: PSLE Science Paper Analysis

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