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Magnetism.pptx
Magnetism is the ability of magnets to attract certain substances like iron. A shepherd named Magnes discovered magnetism when his iron stick got stuck to a stone on the ground. There are natural magnets found in nature called lodestones and artificial magnets that are magnetized artificially. Magnets have a magnetic field and properties like having two poles, attracting magnetic materials, and aligning in the north-south direction when suspended. Magnets are used for compasses, motors, speakers and lifting heavy loads. They can lose their magnetism through heating, hammering or improper storage.
Magnetism.pptx
- 1. Aryaman Sharma –6A Magnetism
- 2. Long ago, inancient Greece, there lived a shepherd named Magnes. He used to take his herd of sheep to the nearby mountains for grazing. In the evening he used a stick to collect his cattle back home. One day he carried a iron stick. While he was beating his stick got stuck on the ground to a stone. He tried pulling it out and had to apply force to successfully do so. He was surprised. He thought there was some evil spirit in the stick or the rock. History
- 3. Any substance whichhas the ability to attract certain substances is called Magnet. The phenomenon by which magnets attract certain substances is called Magnetism.
- 4. Properties of aMagnet 1. Magnet attracts magnetic substances. 2. A freely suspended magnet always rests in the north- south direction. 3. The magnetic pull or magnetic influence is stronger near the ends of the magnet. 4. Poles exists in pairs. 5. Unlike poles attract and like poles repel.
- 5. Properties of aMagnet
- 6. Types of Magnets NaturalMagnet Lodestone was the magnet found occurring naturally in the earth’s crust. Lodestone means ‘leading stone’. It helped people find their way on land and sea. Artificial Magnet Artificial magnets are those magnets which have been imparted the properties of the magnet by artificial means.
- 7. Magnetic Field There isa magnetic field in the area around a magnet. The magnet exerts its influence or the force within the area. Any magnetic object kept within the area will experience a pull towards the magnet.
- 8. Magnets formed dueto electric current are called electromagnets. Temporary magnets lose their magnetism as soon as the cause producing it is removed. Electromagnets are temporary magnets. Permanent magnets are those that retain their magnetised for a long time. Temporary and Permanent Magnets
- 9. Uses of Magnets 1.You can use a magnet to find a pin/needle dropped on the floor. 2. Magnets are used in making magnetic stickers and toys. 3. Magnets are used by doctors to pull out small iron particles from the wounds of the victims of accidents. 4. Magnet in a magnetic compass can help find the directions. 5. Electromagnets are used in the door bells, electric motors, televisions sets, computers, speakers, ATM cards etc. 6. Electromagnets are used to lift heavy loads in warehouse.
- 10. Compass A magnetic compassis a device used to determine the direction. It is essentially made up of a magnetic needle which is free to swing about a pivot at its centre. The needle always come to rest pointing towards the earth's north-south direction.
- 11. The process bywhich a magnet loses its properties is called demagnetisation. Magnets can lose their strength •If hammered or dropped. •If heated. •If not stored properly. Demagnetisation
- 12. Storing Magnets To preservemagnetised for a long time, magnets are stored in magnetic keepers. Magnetic keepers are made of simple pieces of soft iron. They are kept in contact with the opposite pole of a pair of bar magnets or across the poles of a horseshoe magnet. They help to preserve the magnetic lines of force.