Divirta-se com a Física: Aprenda a fazer um motor homopolar

Summary

In this video, Professor Atila demonstrates a simple experiment using a homopolar electric motor. The experiment requires a battery, a coil of wire, and a cylindrical object as a mold. A spiral is created from the wire around the mold, with one end forming a hook. The demonstration explains how electric and magnetic forces interact to cause the spiral to spin around the battery. This experiment highlights the principles of electricity and magnetism in a hands-on and accessible way.

Takeaways

• 😀 The experiment involves creating a homopolar motor using simple materials: a AA battery, copper wire, and a small magnet.
• 😀 The motor is called a 'homopolar motor' due to the direct current (DC) used in the setup.
• 😀 To set up the motor, you'll need a cylindrical mold, which can be any object with a diameter larger than the AA battery.
• 😀 The copper wire is coiled into a spiral around the mold, with one end forming a small hook that will interact with the battery's terminals.
• 😀 The other end of the copper wire forms a flat circle to ensure the magnet can freely pass through it.
• 😀 The final setup results in a spiral with a flat base on one side and a hook on the other side.
• 😀 The motor operates by utilizing two physical principles: electricity and magnetism.
• 😀 The magnetic field from the battery interacts with the electric current flowing through the wire, creating a tangential force.
• 😀 This interaction between the magnetic field and the electric current causes the spiral to rotate around the battery.
• 😀 The spinning motion of the spiral is a demonstration of the Lorentz force, which is the basis of how electric motors work.
• 😀 The experiment is simple and demonstrates fundamental concepts of electromagnetism in a hands-on, visual way.

Q & A

What type of motor is being demonstrated in the experiment?

The motor being demonstrated is an electric motor, specifically known as a homopolar motor.

What materials are needed to create the homopolar motor in this experiment?

The materials needed are a wire, a small AA battery, a piece of magnetic material (such as a magnet), and a cylindrical mold. In this case, the instructor is using a chalk brush as the mold.

Why is it important that the diameter of the mold is larger than the diameter of the battery?

The mold must have a diameter larger than the battery to allow enough space for the components to fit and function correctly. The wire is wrapped around the mold and needs to rotate freely around the battery.

How is the wire shaped in the experiment?

The wire is wrapped into a spiral around the mold. One end of the spiral is shaped into a circle, and the other is turned into a hook facing inward.

What role does the hook at the end of the wire play in the experiment?

The hook is designed to hold the wire in place while ensuring that it can make contact with the battery and complete the circuit for the motor to work.

What causes the spiral to spin around the battery in this experiment?

The spiral spins around the battery due to the interaction of two forces: the magnetic force and the electric current. The magnetic field from the battery interacts with the current flowing through the wire, generating a force that causes the rotation.

What physical principles are at play to make the motor work?

The motor works based on the principles of electromagnetism, where an electric current generates a magnetic field, and the magnetic field interacts with the current to produce mechanical motion. Specifically, the electric current is oriented tangentially to the magnetic field, which induces a force that causes the spiral to rotate.

What is the relationship between the electric current and the magnetic field in this experiment?

The electric current flowing through the wire creates a magnetic field around it. This magnetic field interacts with the external magnetic field produced by the battery, resulting in a force that makes the spiral wire rotate.

What might happen if the wire were not properly shaped or the mold was the wrong size?

If the wire is not shaped correctly or if the mold is the wrong size, the motor might not function properly. The wire may not make proper contact with the battery or could become misaligned, preventing the electric current from flowing correctly and disrupting the rotational motion.

Why is this type of experiment referred to as a homopolar motor?

This is called a homopolar motor because it uses a direct current (DC) power source, where the current flows in only one direction. The term 'homopolar' refers to the type of magnetic field used, which remains consistent (or 'polar') in direction, as opposed to alternating current (AC) motors.