CBSE Class 6 Science Revision Notes Chapter 13

CBSE Class 6 Science Chapter 13 Revision Notes – Fun with Magnets

Class 6 Science Chapter 13 Notes are concise and explain all of the concepts and terminologies related to magnets. It includes topics such as the properties of magnets, different types, shapes of magnets, and classification of magnets. These notes are as per the revised CBSE Syllabus and were constructed keeping in mind the requirements of the students. 

Students can access these notes at their convenience from the Extramarks website. The Class 6 Science Chapter 13 Notes are comprehensive and help students gain an in-depth understanding of this chapter. These notes are ideal to revise important points before an exam. 

Revision Notes for CBSE Class 6 Science Chapter 13

Access Class 6 Science Chapter 13 – Fun with Magnets Notes in 30 Minutes

Magnet

1. Materials like iron, nickel, and cobalt are attracted by the magnet, as it is a substance that attracts such materials.
2. The first person to discover a magnet was Magnas, a Greek shepherd.
3. Magnets are classified into two types, which are as follows.
   • Natural Magnet:

• The magnet which is easily discovered in nature is called a natural magnet.
• For example, Magnetite and Lodestone.

• Artificial Magnet: 

• The magnets made by human beings are known as artificial magnets.
• For example, a horseshoe magnet and a bar magnet.

Magnetic Force

1. The force that a magnet uses to draw an object to itself is known as a magnetic force.
2. Once two magnets are near each other or come together, they exert a force on one another, just as electrical power does. This force is an example of magnetic force.

Poles of a Magnet

1. Magnetic materials like iron filings do not evenly cling to each and every area of a magnet when the magnet comes in contact with the iron filings. They tend to cling to specific parts of the magnet more than others. These are called the poles of the magnet. 
2. The magnetic forces present at the ends of the magnet or at the poles are powerful.
3. Each magnet has two poles at its extreme ends.
4. The two poles in a magnet are the North and South poles.

North Pole

The end of the magnet that faces northward is considered to be the North Pole.

South Pole

The end of the magnet facing south is considered to be the South Pole.

• The N-S axis of a  magnet when it is freely hanging is well positioned.
• Similar poles repel one another, but opposite poles are drawn to one another.
• Magnetic poles are always found in pairs of two.
• A bar magnet is classified into four poles after it is divided in half, with a North and South Pole on both sides.

Different Types and Shapes of Magnets

Magnets are classified into several categories on the basis of their shapes, as listed below:Bar magnet

1. Horseshoe magnet
2. The ball-ended magnet is also known as  a dumb-bell 
3. Magnetic needle
4. Cylindrical magnet
5. Artificial magnet
6. Lodestone, also known as a natural magnet
7. Ring or disc-shape magnet

Classification of Substances Based on Attraction to Magnets

• Magnetic Substances: Magnets are capable of attracting materials like iron, filings, etc. Those materials are known as magnetic substances.
• Non-Magnetic Substances: Materials that are not attracted to a magnet, like plastic, wood, paper, most metals, and various other materials, are known as non-magnetic substances.

Methods for Making Your Own Magnet

1. Single Touch Method: When a magnet is massaged against an iron object over its length from one end to the other, just like combing someone’s hair, it gets magnetised.
2. Double Touch Method: The bar or the object turns into a magnet after it is rubbed by two strong bar magnets possessing equivalent strength of their opposing poles at the centre and facing in different directions.
3. Using Electric Current: The bar which is magnetic is placed in a conductor’s coils, and an electrical current is put through the wire coils. 

Properties of Magnet

1. The two poles of any magnet are the North Pole and the South Pole.
2. Similar poles always repel when they come into contact with each other.
3.  Poles that are opposites are attracted to each other.
4. A magnet contains a pair of poles that are different from one another.
5. Monopolar or single pole magnets do not exist. Only bipolar magnets exist, which means they have two poles.

Applications of Magnet

• Compass Needle: The compass consists of a tiny glass container along with a magnetised needle spinning on an aluminium nail. The needle has an unrestrained rotation as the earth is considered to be a giant magnet that points north-south. The compass is well aligned with the earth’s magnetic field.
• Enormous amounts of iron, like scrap iron, are moved in factories with the help of a magnet.
• Doorbells as well as chimes contain an electromagnet.
• Steel splinters are removed from wounds by surgeons in hospitals using permanent magnets that are also present in loudspeakers.
• Magnets are used to segregate iron and steel from non-magnetic substances while producing telephones, electric bells, and other devices. 
• Credit cards, ATM cards, and identity cards comprise a strip that is made of a magnetic substance that stores information.
• Televisions and computer monitors comprise magnets as one of their components.
• Magnetic substances are used to store data on computer hard disks, video and audio cassettes.
• Certain magnets are used in the scrapyard to lift some iron-based materials.

Demagnetisation (Loss of Magnetic Property of a Magnet)

• A magnet loses its magnetic property after it is hammered, heated, inadequately stored, or dropped from a high altitude with force.
• Induction can lead to the destruction of each pole by the other if two bar magnets kept together with the same poles are not facing in a similar direction.
• The prime way to preserve bar magnets in pairs is by throwing them from a height of different poles beside each other. 
• Material such as a piece of soft iron must be placed over the poles of a horseshoe magnet to preserve it.

Taking Care of Magnets

• Magnets must be preserved in non-magnetic materials like cardboard or wood when not in use. 
• Since bar magnets lose their magnetic properties when the poles are kept exposed for an extended period of time, a piece of wood or soft iron called a magnetic keeper is used to store magnets. A keeper is placed between a pair of bar magnets with opposite poles to maintain the magnetism of the objects.