UNIT 1

Project Number: 2023-1-PL01-KA220-SCH-000164042

UNIT 1: Magnetic Field and Current

Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Education and Culture Executive Agency (EACEA). Neither the European Union nor EACEA can be held responsible for them.

Introduction

In this activity we will learn the basics of electricity and magnets and put them together to understand the working principle of an electric motor.

Source: freepik.com

Learning Outcomes

Student:

• Recognises the magnet and identifies that it has poles.
• Gives examples of the use of magnets in daily life.
• Understands the relationship between magnetic field and electric current.

Source: freepik.com

What is the relationship between magnetic field and current?

The invisible force field that forms around magnets and can affect electrically charged particles is known as the magnetic field. This field, which explains the attractive or repulsive effects of magnets, is one of the fundamental concepts in electricity and magnetism.

Source: freepik.com

Let's take a closer look at these

Magnet

• Materials that create a magnetic field around them and attract magnetic substances such as iron, nickel and cobalt are called magnets.
• A magnet has two poles called north and south.
• While the same poles of two magnets brought closer to each other repel each other, different poles attract each other.

Magnetic Field

• There is an invisible field around the magnet, but its effect can be felt.

This field is called "magnetic field".

• The magnetic field shows how far the power of the magnet extends. This field is stronger near the magnet and weaker the farther away it is.
• If you place a sheet of paper on a magnet and pour iron powders on the paper, you can observe the magnetic field lines in the plane of the paper.

What happens if we take a magnet and cut it into two pieces?

• If you cut a magnet in half, each part will still have a north and south pole. The atoms inside the magnet act like little magnets and are all aligned in the same direction. This alignment causes one side of the magnet to have a north pole and the other side to have a south pole.
• This is a fundamental property of magnets. So the magnetic lines of force inside the magnet always come out of the north pole and go towards the south pole.
• Therefore, we can say that a magnet consists of a combination of many small magnetic regions at the atomic level, based on the fact that each part we obtain by dividing a magnet shows magnet properties. We can also use this to explain the interaction of magnets with magnetic materials.

Turning Non-Magnets Into Magnets

As can be seen from the image, magnetic materials that do not exhibit spontaneous magnet properties also have small magnetic regions at the atomic level within themselves. However, since the magnetic fields that make up these materials dampen each other, they do not show magnetic properties as they are found in nature.

Turning Non-Magnets Into Magnets

However, it is still possible to turn them into magnets with an external influence. The simplest way is to rub these materials against a magnet. You have observed that when you rub a magnet against an iron, the iron becomes a magnet and attracts magnetic materials such as paper clips and needles. In this way, we give the iron a magnet property, albeit temporarily.

Electricity Can Create Magnetism

• Another way to magnetise magnetic materials that do not show magnet properties is to pass current through them.
• This is actually a situation that scientists have discovered by coincidence. Danish physicist Hans Christian Oersted, while continuing his studies on the electric circuit, accidentally noticed that the needle of a compass near the circuit deviated when electric current passed through the circuit.
• As a result of his studies, Oersted observed that when the current passes through a conductive wire, it creates a magnetic field around the wire and two current- carrying wires attract or repel each other according to the direction of the current.

Source: freepik.com

From Discovery to Invention

• Orsted's findings influenced the work of scientists such as Michael Faraday and Joseph Henry on electromagnetism. Thus, it was understood that
• there is a relationship between electricity and magnetism.

The magnetisation feature you see here is actually the basis of the working principle of electric motors and generators. Let's do a learning activity to understand this better. Scan the QR code to learn more about how this principle powers everyday machines!

Learning activity: Information for the teacher

In this activity you will explore how magnets play a role in theoperation of electric motors using a simple electric motor model.

• Instructions:

Scan the QR code to access the simulation of a simple electric motor. Observe what happens when electric current flows through the coil near a magnet.

• Write down and explain your observations

What did you observe? Why do you think this happened? What conclusions did you draw as a result of your observations? What do you think is the relationship between magnetic field and current?