# Magnets and magnetic fields

> What you need for the magnetic properties in Chapter 1


## Objectives

- Describe the magnetic field around a magnet and the rule of the poles: like poles repel, unlike poles attract.
- Name the materials a magnet attracts strongly (iron, cobalt, nickel) and explain why 'magnets attract all metals' is wrong.
- Say what it means for a substance to be attracted to, or repelled by, an external magnetic field.

## 1. Magnets and magnetic fields: from zero




## 2. Metal, but not pulled

Why doesn't the magnet pull the can?

- A magnet strongly attracts only some materials, like iron, and aluminum is not one of them ✓
- Magnets attract all metals, so the can must have a plastic coating
- The can is too light for the magnet to notice

A magnet strongly attracts only some materials, such as iron, cobalt and nickel. Aluminum is a metal, but a magnet doesn't noticeably pull it, so the can is not pulled.

[ar-EG] الـ magnet بيجذب بقوة مواد معيّنة تحديدًا، زي الـ iron والـ cobalt والـ nickel. الـ aluminum metal، لكن الـ magnet مش بيشده بشكل ملحوظ، عشان كده العلبة مش بتتشد.
## 3. The magnetic field

A bar magnet and its magnetic field lines, from N to S outside the magnet magnetic field The region around a magnet where its magnetic force acts. The field is invisible. Put iron filings near the magnet and they line up along these lines. A magnet attracts all metals.


## 4. Poles: pull or push

Every magnet has two **poles**: north (N) and south (S). Unlike poles attract. Like poles repel. The rule of the poles **Like poles repel; unlike poles attract.** So a magnetic field can pull something in, or push it away. You'll need both ideas in Chapter 1.


## 5. Pulled or not?

Two bar magnets lie end to end. The S pole of one faces the S pole of the other. What happens?

- Nothing, unless they touch
- They attract
- They repel ✓

S facing S means like poles, and like poles repel, so the two magnets push each other apart. Magnets act on each other across the gap without touching.

[ar-EG] الـ S قصاد الـ S يبقوا like poles، والـ like poles بتتنافر، فالاتنين magnets بيزقّوا بعض بعيد. والـ magnets بتأثر على بعض عبر المسافة من غير ما تلمس بعض.
## 6. Summary

Being a metal is not enough to be pulled by a magnet A magnet has a **magnetic field** around it: the region where its magnetic force acts. Like poles repel; unlike poles attract. A magnet strongly attracts iron, cobalt and nickel, not all metals. Chapter 1 uses these words: a substance **attracts to the external magnetic field**, or it **repels the external magnetic field**. Magnetic properties of transition elements, in Chapter 1. Can you explain why a magnet pulls a steel door but not an aluminum can?



Chapter: Transition Elements (https://yaani.ai/ar/learn/chemistry/chem-s3-en.ch1)
Source: https://yaani.ai/ar/lesson/chem-s3-en.lesson-phys.magnetic-field