S72 Students will investigate the properties of electricity

S-72 Students will investigate the properties of electricity and magnetism? • What is a magnet? • What are the two poles called?

Chapter 21 Magnetism SPS 10 Students will investigate the properties of electricity and magnetism. c. Investigate applications of magnetism and/or its relationship to the movement of electrical charge as it relates to d. - electromagnets e. - simple motors f. - permanent magnets

21. 1 Magnets and Magnetics Fields How do magnetic poles interact? How can a magnetic field affect a magnet that enters the field? Why are some materials magnetic while others are not?

21. 1 Magnets and Mag Fields How do magnetic poles interact? • Magnetic force – the push or pull a magnet exerts on – Another magnet – On iron or a similar metal – On moving charges

21. 1 Magnets and Mag Fields How do magnetic poles interact? • Magnets have two poles – North and south – Like poles repel – Opposite poles attract

21. 1 Magnets and Mag Fields How can a magnetic field affect a magnet that enters the field? • Magnetic field – an area around a magnet that will attract or repel other magnets – Begin at the north pole – End at the south pole – Can be seen using iron dust – Arrows point in the direction of force on a north pole – The earth has a magnetic field

21. 1 Magnets and Mag Fields Why are some materials magnetic while others are not? • Magnetic fields are cause by spinning electrons – Most of the time magnets are paired, and the fields cancel out – Magnetic domain – a region that has a large number of electrons with fields in the same direction – Magnetized – most of the domains are pointed in the same direction

S-73 Doin’ The Happy Test Day Dance

S-74 What does an electron do to create a magnetic field? What is a domain? What must happen to the domains in a substance for it to be a magnet?

21. 2 Electromagnetism How can an electric charge create a magnetic field? How is an electromagnet controlled? How does an electric motors work?

21. 2 Electromagnetism How can an electric charge create a magnetic field? • Electricity and magnetism are two faces of the electromagnetic force. – Electric force from particles – Magnetic force caused by spinning of charged particles

21. 2 Electromagnetism How can an electric charge create a magnetic field? • Magnetic fields are formed by moving electric charges (Hans Christian Oersted) – If the charge moves down a wire, the magnetic field circles the wire

21. 2 Electromagnetism How can an electric charge create a magnetic field? • Magnetic fields will put a force on a current carrying wire – These ideas are used to build • Electromagnets • Electric motors • Electric generators

21. 2 Electromagnetism How is an electromagnet controlled? • Solenoid – a coil of current carrying wire that produces a magnetic field – A ferromagnetic rod inside a will increase the field – This is an electromagnet solenoid strength

21. 2 Electromagnetism How is an electromagnet controlled? • The strength of an electromagnet can be controlled by – Changing the current – Changing the number of loops – Changing the type of core

21. 2 Electromagnetism How does an electric motor work? • Electric motor – Electricity produces an electromagnet – The electromagnet is attracted or repelled by another magnet – A commutator ring changes the poles as after ½ a spin

S-75 What is needed to make an electromagnet work?

S-76 Using the right hand rule, what is the direction of the magnetic field around a wire if the current is traveling upward?

21. 3 Electrical Energy Generation How does a generator work? What are some sources of electrical energy in the United States?

21. 3 Electrical Energy Gen. How does a generator work? • Electromagnetic Induction – producing a current by – Moving an electrical conductor in a magnetic field – As simple as running a magnet through a coil – The faster the movement the higher the current – Current stops when the motion stops

21. 3 Electrical Energy Gen. How does a generator work? • Generator – converts mechanical energy to electrical energy – Movement to current – Rotates a coil in a magnetic field – Power plants current produce AC

21. 3 Electrical Energy Gen. How does a generator work? • Generator Simulation – Loops of wire are spun – Whatever runs the power plant spins the wire – Every half spin the direction of current changes – Takes about 3300 watts to run a house

21. 3 Electrical Energy Gen. What are some sources of electrical energy in the United States? • Sources of energy in the US – 49. 8% – 19. 9% – 17. 9% – 6. 5% – 3% – 2. 3% Coal Nuclear Natural Gas Hydroelectric Petroleum Wind, Solar, Geothermal, Biomass