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Magnetism in the 21st Century
Transcript of Magnetism in the 21st Century
By: Will Powe and Cameron Mills Magnetism is Everwhere! General Info: Living in the 21st century, we experience magnets everywhere we go.
Sometimes we use things and don’t even know it’s a magnet. Magnets can be found anywhere from medicine, astronomy, electronics, navigation, and even toys!
We will show some examples of common items that function using magnets. Magnetism in medicine An MRI is a powerful x-ray to find tumors, bleeding, injury, blood vessel diseases, or infection The biggest and most important component in an MRI system is the magnet.
Magnets in a MRI are VERY powerful. Magnets used in a MRI measure anywhere from 0.5-tesla to 2-telsa (equivalent to 5,000 to 20,000 gauss). The earth’s magnetic field is 0.5-gauss. So a magnet in a MRI is 10,000 times more powerful then the earth’s magnetic field!
Metal objects can become dangerous if they are taken into the scan room. Stuff like paperclips, pens, keys, scissors, hemostats, stethoscopes and any other small objects can be pulled out of pockets and off the body without warning. They can then fly toward the opening of the magnet (where the patient is placed) at very high speeds, posing a threat to everyone in the room. Credit Cards, bank cards and anything else with magnetic encoding will be erased by most MRI systems. magnetism in astronomy Magnetars are what magnetism can relate to in space- they begin their life when a rapidly rotating large star explodes and collapses into a much smaller mass, causing the hot neutronic liquid to rise and fall from the center to the crust, which causes a 'dynamo' effect. When this event occurs, an incredibly powerful magnetic field is produced. magnetism in electronics When the electrical current flowing through the voice coil changes direction, the coil's polar orientation reverses. This changes the magnetic forces between the voice coil and the permanent magnet, moving the coil and attached diaphragm back and forth. Magnetism in Navigation A magnetic compass consists of a small, lightweight magnet balanced on a nearly frictionless pivot point. The magnet is generally called a needle. Think of the Earth as having a gigantic bar magnet buried inside. In order for the north end of the compass to point toward the North Pole, you have to assume that the buried bar magnet has its south end at the North Pole, as shown in the diagram at the right. If you think of the world this way, then you can see that the normal "opposites attract" rule of magnets would cause the north end of the compass needle to point toward the south end of the buried bar magnet. So the compass points toward the North Pole. Magnetism in Toys Wooly Willy is one of the best known toys that use magnets. It operates via partially filling a plastic box with the background as a man's face, with a magnet on a string to be used as a sort of pen to 'draw' designs on the face. Many different hairstyles and facial hair styles can be created, and some are even suggested on the sides of the box.