Levitating Barbecue! Electromagnetic Induction

Summary

In this exciting demonstration, a massive alternating current passes through a coil, causing a 1 kg aluminium plate to levitate and vibrate dramatically. The video traces this phenomenon back to Michael Faraday's groundbreaking experiments at the Royal Institution in London, where he discovered electromagnetic induction. Using Faraday's original principles, a changing magnetic field in a coil induces currents in nearby conductors, producing opposing magnetic fields that can levitate objects, light bulbs, and even heat metal. The experiment combines history, science, and spectacle, showcasing Faraday's law in action while entertaining viewers with levitating plates, glowing bulbs, and a sizzling 'flying BBQ.'

Takeaways

• 😀 A large alternating electric current is passed through a coil of thick wire to induce effects like plate levitation.
• 😀 The aluminum plate vibrates at twice the frequency of the current passing through the coil, creating a unique sound.
• 😀 The process demonstrated is linked to Faraday's electromagnetic induction, where a changing magnetic field induces current in a conductor.
• 😀 Faraday's famous experiment in 1831 used an iron ring and coils of wire to demonstrate that a changing magnetic field induces an electric current.
• 😀 Faraday's experiment required manually insulating wire, which took significant time and effort, highlighting the challenges of the time.
• 😀 When Faraday connected a battery to one coil, he observed a pulse of current in the second coil, showing the link between magnetic fields and induced current.
• 😀 The interaction of magnetic fields between the coils would cause them to repel each other, a key observation in Faraday's work.
• 😀 In the demonstration, a 800A alternating current passes through the bottom coil, creating a constantly changing magnetic field.
• 😀 The induced currents in the aluminum plate create an opposing magnetic field, which causes the plate to levitate.
• 😀 The levitation setup not only demonstrates electromagnetic induction but also powers lightbulbs and heats up the plate, showcasing practical applications.
• 😀 The plate becomes hot due to induced currents dissipating energy as heat, a process similar to how a toaster element works.

Q & A

What is the main principle demonstrated in the video?

The video demonstrates Faraday's law of electromagnetic induction, showing how a changing magnetic field can induce an electric current in a conductor.

How is the aluminum plate made to levitate in the experiment?

The aluminum plate levitates because the alternating current in the coil creates a changing magnetic field, which induces eddy currents in the plate. These eddy currents generate an opposing magnetic field, causing the plate to float.

Why does the aluminum plate vibrate at twice the frequency of the current?

The vibration occurs because the induced currents in the plate produce a magnetic field that interacts with the coil's field, generating forces that oscillate at twice the AC frequency.

What historical experiment by Faraday does this demonstration relate to?

It relates to Faraday's 1831 experiment where he wrapped two coils of wire around an iron ring and discovered that a changing magnetic field in one coil induced a current in the second coil.

Why was insulating the wire such a significant effort in Faraday's time?

In 1831, insulated wire was not commercially available, so Faraday had to manually insulate the wire as he wound it around the iron ring, which took about ten working days.

How does the demonstration show the heating effect of induced currents?

The induced currents in the aluminum plate dissipate energy as heat, which can be measured by touch or by adding water to see the temperature rise, similar to how a toaster element works.

What other practical effect of induced currents is shown in the video?

The induced currents are also used to make lightbulbs glow when placed near the plate, demonstrating that energy from the current can be transferred to electrical devices.

What role does the alternating current play in this experiment?

The alternating current ensures the magnetic field is constantly changing, which is necessary for inducing current in the aluminum plate according to Faraday’s law.

Why is the aluminum plate used instead of a second coil in the modern demonstration?

The aluminum plate serves the same function as a second coil by allowing eddy currents to form and interact with the magnetic field, providing a dramatic visual effect like levitation.

What does the experiment reveal about the relationship between electricity and magnetism?

It shows that not only does electric current create a magnetic field, but a changing magnetic field can also create electric current, demonstrating the reciprocal relationship between electricity and magnetism.

How does this demonstration connect to Faraday's original lab at the Royal Institution?

The demonstration recreates the effects Faraday explored using modern equipment, while the lab itself preserves Faraday's original apparatus and setup, illustrating the historical context of his discoveries.