Magnets: Properties and Uses

Magnets: Properties and Uses

• Magnets are special stones or man-made objects (iron or steel) that interact with certain metals.
• Natural magnets, like magnetite, attract iron.
• Man-made magnets come in various shapes (U-shaped, horseshoe, bar, rod, ring, button), depending on their application.

Magnetic Materials and Interactions

• Magnets attract certain materials (magnetic materials): iron, nickel, cobalt, and steel.
• Examples of magnetic materials include nails, paper clips, and steel locks.
• Non-magnetic materials are not attracted by magnets, such as gold, silver, aluminium, copper, wood, paper, plastic, glass, and clay.
• Magnets have two poles: north (N) and south (S). The strongest magnetic force is at the poles.

Magnetic Poles and Interactions

• Like poles (N-N or S-S) repel each other.
• Unlike poles (N-S) attract each other.
• Attraction between unlike poles is stronger than repulsion between like poles.

Force and its Effects

• Force is a push or pull that can change an object's motion, speed, direction, shape, or cause a moving object to stop.
• Examples: pushing a car, pulling a trolley, squeezing a lemon, kicking a ball.
• Friction is a force that slows or stops a moving object.

Uses of Magnets

• Magnets are found in many everyday devices, including telephones, headphones, speakers, and some appliances.
• Small electromagnets are used in computers and video recorders for data handling purposes.
• Refrigerator doors often have magnets to keep them closed due to the steel in the refrigerator itself.

Electromagnets

• Electromagnets are temporary magnets that only act as magnets when electricity flows through them.