These DAV Class 6 Science Notes and DAV Class 6 Science Chapter 13 Notes – Magnets act as excellent revision resources, particularly in preparation for board exams.
Magnets Class 6 DAV Notes
→ Discovery of Magnet: Magnet was discovered by a shepherd named Magnes about 4000 years ago. He lived at a place called Magnesia in Northern Greece.
→ Loadstone: A long piece of magnetite (natural magnet) always points in one particular direction only; when suspended freely. Due to this, magnetite is also called loadstone’.
→ Magnet: Magnet is a material which can attract iron metal and articles made of iron.
→ Natural Magnet: Magnet which is found in nature is called natural magnet.
→ Artificial Magnet: Magnet which is made by human is called artificial magnet.
→ Magnetic Material: Materials which can be attracted by a magnet are called magnetic materials, e.g. iron, nickel, steel, cobalt and alloys of certain metals.
→ Non-magnetic Material: Materials which cannot be attracted by a magnet are called non-magnetic materials.
→ Shapes of Magnet: Bar magnet is most commonly used shape of magnet. Apart from that, artificial magnets are also made in the shape of horse-shoe, needle, ball-ended and circular magnets.
→ Permanent Magnet: A magnet which retains its magnetic property for a long time is called permanent magnet.
→ Temporary Magnet: A magnet which retains its magnetic property for a short duration is called temporary magnet. Temporary magnets can be made very strong; compared to permanent magnets.
→ Strength of Magnet: The quantum of attractive force of a magnet gives its strength. If the attractive force is more, the magnet is stronger.
→ Poles of a Magnet: The strength of a magnet is the maximum at its two ends. The ends of a magnet are called its pole. A magnet has two poles, viz. north pole and south pole. The north pole is also called north seeking pole of a magnet. Similarly, the south pole is also called south seeking pole of a magnet.
→ When a bar magnet is suspended freely, it always points in the north south direction. The north pole points towards the north and the south pole points towards the north.
→ Interaction between poles of two magnets: When north pole of a bar magnet is brought near the north pole of another bar magnet, both of them repel each other. Similarly, when south pole of a bar magnet is brought near the south pole of another bar magnet, both of them repel each other. On the contrary, when the north pole of a bar magnet is brought near the south pole of another bar magnet, both of them attract each other.
“Like poles of two magnets repel each other. Unlike poles of two magnets attract each other.” Earth as a Magnet: The earth also has magnetic property. Its north pole is near its geographic south, while its south pole is near its geographic north.
→ Making a Magnet: A magnet can be made by various methods. Some of them are given below:
→ Suspend an iron rod in the N – S direction and gently hammer it repeatedly from one end. This will give you a weak magnet.
→ Take an iron rod and rub a bar magnet (without lifting) along its length; starting from one end. Doing this repeatedly, will give you a magnet.
→ When an iron/steel needle is placed near a bar magnet for some time, the needle acquires magnetic property.
→ Compass Needle: Compass needle is a simple device which has been in use for finding direction. The compass needle is fixed on a pivot on which it can freely move. This is enclosed in small box: covered with glass top. The compass needle always points in N – S direction and thus can be used for finding directions.
→ Some Interesting Facts About Magnets:
(a) Magnet loses its magnetic property when it is heated or mishandled (dropped or hammered).
(b) If a magnet is not stored properly, its strength reduces in due course of time. Bar magnets are kept in pairs; with their unlike poles on the same side and separated by a piece of wood. Two pieces of soft iron are placed at the ends. This arrangement is called ‘magnetic keepars’.
(c) If a magnetic material is kept near a computer, or a cell phone or a DVD or an audio cassette; it can erase the memory/information from them.
→ Magnet: A material which can attract magnetic materials; like iron, nickel and cobalt; is called a magnet.
→ Poles of a magnet: The two ends of a magnet are called its pole.
→ South seeking pole: The pole of a magnet which points in the south direction; when the magnet is suspended freely; is called its south seeking pole.
→ North seeking pole: The pole of a magnet which points in the north direction; when the magnet is suspended freely; is called its north seeking pole.
→ Electromagnet: A temporary magnet which is made because of effect of electricity is called electromagnet.