* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Magnetism - BAschools.org
Van Allen radiation belt wikipedia , lookup
Magnetic stripe card wikipedia , lookup
Maxwell's equations wikipedia , lookup
Electrical resistance and conductance wikipedia , lookup
Geomagnetic storm wikipedia , lookup
Friction-plate electromagnetic couplings wikipedia , lookup
Neutron magnetic moment wikipedia , lookup
Magnetometer wikipedia , lookup
Skin effect wikipedia , lookup
Magnetic monopole wikipedia , lookup
Mathematical descriptions of the electromagnetic field wikipedia , lookup
Giant magnetoresistance wikipedia , lookup
Earth's magnetic field wikipedia , lookup
Electromotive force wikipedia , lookup
Lorentz force wikipedia , lookup
History of electromagnetic theory wikipedia , lookup
Magnetoreception wikipedia , lookup
Magnetotactic bacteria wikipedia , lookup
Electromagnetic field wikipedia , lookup
Multiferroics wikipedia , lookup
Magnetohydrodynamics wikipedia , lookup
Electromagnetism wikipedia , lookup
Electricity wikipedia , lookup
History of electrochemistry wikipedia , lookup
Magnetotellurics wikipedia , lookup
Magnetochemistry wikipedia , lookup
Electric machine wikipedia , lookup
Electromagnet wikipedia , lookup
Eddy current wikipedia , lookup
Ferromagnetism wikipedia , lookup
History of geomagnetism wikipedia , lookup
Chapter 17 magnetism – the properties and interactions between magnets based on the alignment of particles in a substance magnetic – the ability of an object to make forces on magnets and other magnetic objects three types: permanent magnet temporary magnet electromagnet The earliest magnets were found naturally in the mineral magnetite which is abundant the rock-type lodestone. These magnets were used by the ancient peoples as compasses to guide sailing vessels. material that keeps its magnetic properties ex: your normal understanding of a magnet – fridge magnets, bar magnets…etc. material which acts like a permanent magnet when inside of a strong magnetic field but lose their magnetism outside of it paperclips, nails, other soft iron items…etc. used in motors device which changes electrical energy into mechanical energy we use permanent magnets and electromagnets to make electric motors and generators ▪ generators turn mechanical energy to electrical energy these work by changing the direction of the electric current helix of wire tightly wrapped around an iron core – acts like a magnet when current is applied to it strength of the magnet varies with the current [more current, more magnetized] …[review] is based on the alignment of particles in a substance. all atoms have moving electrical charges [electrons] these moving electrons cause a magnetic field this causes the Faraday Effect Faraday Effect Clip The magnetic field lines around horseshoe and disk magnets are closest together and strongest at the magnet’s poles. Unlike poles of magnets attract each other Like poles of magnets repel. are stronger nearer to the top of magnet create North [pull north] & South [pull south] poles a pole is where the force of the magnet is the strongest each pole is attracted to the other [hence the swirls of field from N to S or from S to N] The earth is like a giant magnet! The nickel iron core of the earth gives the earth a magnetic field much like a bar magnet. atoms in an object behave like tiny magnets In an area of an object where all of the particles have a similar magnetic field is called a domain the particles of most objects are not aligned …[the particles of most object are not aligned] aligning particles will cause an overall magnetic field the force of a magnet depends on the alignment of its particles Another magnet can cause the alignment of an object’s electrons Magnetic substances like iron, cobalt, and nickel are composed of small areas where the groups of atoms are aligned like the poles of a magnet. These regions are called domains. All of the domains of a magnetic substance tend to align themselves in the same direction when placed in a magnetic field. These domains are typically composed of billions of atoms. When an electric current passes through a wire a magnetic field is formed. The direction of the current depends on the directions of the current in the wire, to a position of lower potential energy. A galvanometer is an electromagnet that interacts with a permanent magnet. The stronger the electric current passing through the electromagnet, the more it interacts with the permanent magnet. The greater the current passing through the wires, the stronger the galvanometer interacts with the permanent magnet. We have seen how electricity can produce a magnetic field, but a magnetic field can also produce electricity! How? What is electromagnetic induction? Moving a loop of wire through a magnetic field produces an electric current. This is electromagnetic induction. A generator- used to convert mechanical energy into electrical energy by electromagnetic induction. Simplest Electric Motor Clip How does an electric motor work? Go to the next slide Simple as that!! Direct current versus alternating current – AC vs DC : What’s the difference? Direct current is electrical current which comes from a battery which supplies a constant flow of electricity in one direction. Alternating current is electrical current which comes from a generator. As the electromagnet is rotated in the permanent magnet the direction of the current alternates once for every revolution. Go to this website and click the button for DC then for AC to visually see the difference between the two. You can see that the DC source is a battery – current flows in one direction. The AC source is the generator and the current alternates once for each revolution.