Force A push or pull of an object

Force A push or pull of an object as a result of another object. ü Bar magnet Commonly used magnet (blue is the south pole and red is the north pole). ü Pole The ends of a magnetic field, called north-seeking (N) and south-seeking poles (S). ü Attract A force pulling magnetic materials together. ü Repel A force pushing magnets apart. ü ü Permanent magnet An object that is magnetic all of the time. Induced magnet A magnet that looses its magnetism when removed from a magnetic field. Magnetic field The area around a magnet where the magnetic force has an effect. Compass Magnetic needle that points to magnetic north. ü Electromagnetism Electromagnet A non-permanent magnet turned on and off by controlling the current through it, Solenoid Wire wound into a tight coil, part of an electromagnet. Core Soft iron metal which the solenoid is wrapped around. DC Direct current. DC Motor A coil of wire between two magnets of opposite poles connected to a DC power source. ü ü ü Key Diagrams ü ü ü ü An electromagnet is a non-permanent magnet that can be turned on and off. A basic electromagnet consists of solenoid (coil of wire) containing an iron core. The strength of an electromagnet can be increased by: • Increasing the current • Increase the number of coils • Wrapping the coil around an iron core A DC motor is a coil of wire between 2 magnets of opposite poles connected to a DC power source e. g. a battery. When the motor is in the magnetic field it moves. Check A force that can push (repel) or pull (attract) other magnetic objects. Write Magnetism is a non-contact force. Magnets have two poles; North and South. Opposite poles attract and like poles repel. Permanent magnets can repel other magnets and remain magnetic when removed from a magnetic field. An induced magnet always experience a force of attraction and looses its magnetism when removed from a magnetic field. Magnetic materials include three elements; Iron, Nickle and Cobalt as well as steel which is an alloy of Iron (compound of iron and carbon). A magnetic field cannot be seen but is the region around a magnet where it has a magnetic effect. Iron filings and a plotting compass can both be used to identify a magnetic field. Magnetic field lines show us the direction of a magnetic field (always north to south). Magnetic field lines are more concentrated at the poles; this is where the magnet is strongest. A compass is a magnetic needle mounted on a pivot so that it can move freely around a dial showing direction. Compasses can be used to navigate maps. The geographic north pole is a magnetic south pole. The north pole of magnets (compass needles) are attracted to the north pole of the earth. The earth’s core contains iron. The earth’s magnetic field deflects ionising radiation from space and also creates the Aurora Borealis (Northern lights). Animals including birds, turtles and whales use the earth’s magnetic field for navigation. Cover Definition ü ü Look Science KS 3: Magnetism and Electromagnetism Key Words Key Diagrams Self-quiz using Magnetism Correct Key Points