Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
State of matter wikipedia , lookup
Accretion disk wikipedia , lookup
Electrostatics wikipedia , lookup
Field (physics) wikipedia , lookup
Maxwell's equations wikipedia , lookup
Condensed matter physics wikipedia , lookup
Electromagnetism wikipedia , lookup
Magnetic field wikipedia , lookup
Neutron magnetic moment wikipedia , lookup
Aharonov–Bohm effect wikipedia , lookup
Lorentz force wikipedia , lookup
Magnetic monopole wikipedia , lookup
How can we explain magnetism? Do Now: Why does a compass point north? Magnets •2 poles: North and south S N •Cannot isolate a pole S N S N Like Poles ►2 like poles experience a force of repulsion S N N N S S S N Donut magnet Demo Unlike Poles ►2 unlike signs experience a force of attraction N S N S Compass ► Attracted to magnetic south pole S N Therefore this is magnetic north Earth ► Earth is a huge magnet ► So why does the north pole of a compass point to the north pole of the Earth? Geographic Magnetic South Pole Geographic Magnetic North Pole Ferromagnetic substances ►Substances magnetic Iron Nickel Cobalt that are naturally How do things become magnetized? Magnetism is caused by the spin of the unpaired electrons. When they spin in the same direction, they cause microscopic magnets called domains. If all the domains are aligned, a magnet is formed. Temporary Magnet ► Created when a ferromagnetic substance is brought into close proximity to an easily magnetized substance (domains temporarily align) ► Occurs when the electrons spin in the same direction Magnetic Field Lines If compasses are place around a magnet, we can visualize the field around the magnet. N S Magnetic Fields ►Field lines are called lines of flux ►Defined as north to south ►Strongest where the lines of flux are closest Magnetic Flux Magnetic flux describes the lines of a magnetic field around a magnetized object. Each magnetic flux line is equal to 1 Weber (Wb). The strength of the field, or magnetic flux density (B) is measured in Wb/m2 , or Tesla (T). S S If field lines point in the same direction, N S N S They repel. If field lines point in the opposite direction, S N N S They attract. So why is the Earth magnetic? ► Magnetic charges fields are created by moving Any time a charge moves (current) a magnetic field is created ► Outer Core of Earth is liquid iron and nickel Ferromagnetic substances that have a charge and are moving Magnetic Force •Created when a moving charge passes through a magnetic field •Reason: Charge has a magnetic field and it interacts with another magnetic field •Greatest force is when the charge passes perpendicular to the field Sidenote: ► Planes, DeGaussing ships move through the Earth’s magnetic field. ► Just as moving a charge through a magnetic field creates a force, forcing an object to move through a magnetic field creates electricity ► This needs to be taken into account or else navigational equipment gets jacked up Which produces the greatest force? B (magnetic lines of flux B (magnetic lines of flux ee- B (magnetic lines of flux e- Gamma Rays ► Moving charges through space ► Enter Earth’s magnetic field ► Magnetic force is created ► Gamma Rays get deflected ► The Earth is safe ► http://www.youtube.com/watch?v=0JYkR17 Ud5Q