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demonstrations:5_electricity_and_magnetism:5k_electromagnetic_induction:eddy_currents_in_a_spinning_pie_plate:start
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demonstrations:5_electricity_and_magnetism:5k_electromagnetic_induction:eddy_currents_in_a_spinning_pie_plate:start [2019/02/14 23:33] 127.0.0.1 external edit |
demonstrations:5_electricity_and_magnetism:5k_electromagnetic_induction:eddy_currents_in_a_spinning_pie_plate:start [2020/01/28 18:13] (current) demoroom |
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| ====== Eddy Currents In A Spinning Pie Plate ====== | ====== Eddy Currents In A Spinning Pie Plate ====== | ||
| - | {{tag>eddy currents pie plate needs_review untagged unlocated}} | + | {{tag> eddy_currents electricity_and_magnetism induction lenz newton's_third_law located}} |
| <WRAP box right> | <WRAP box right> | ||
| Line 11: | Line 11: | ||
| ===== Description ===== | ===== Description ===== | ||
| - | Demonstrate Eddy currents in a pie plate Classes Used: Phys 102, 108 | + | Consists of an aluminum pie plate balanced on the tip of a pencil. A magnet is used to induce eddy currents in the plate and spin the plate. |
| - | + | ||
| - | + | ||
| - | Eddy Currents Updated on 05/30/13 | + | |
| - | + | ||
| ===== Purpose ===== | ===== Purpose ===== | ||
| - | + | Demonstrate the induction of [[wp>eddy current|eddy currents]]. Demonstrate induced current/ magnetic fields. Demonstrate Lenz's law/ Faraday's law. Show that Newton's third holds, and the 'drag' experienced by the magnet (and shown by the [[demonstrations:5_electricity_and_magnetism:5k_electromagnetic_induction:magnets_through_copper_tube:start|magnet drop through copper tube demo]]) also translates to rotation of the disk. | |
| - | To demonstrate Eddy currents | + | |
| - | + | ||
| ===== Apparatus ===== | ===== Apparatus ===== | ||
| - | + | * Large aluminum pie plate/ serving plate | |
| - | Large pie plate | + | * Pencil |
| - | Hb2 Pencil | + | * [[demonstrations:9_equipment:lab_stands:start|Lab stand]] |
| - | Small vice | + | * [[demonstrations:9_equipment:magnets:start|Large Neodymium magnet]] |
| - | Neodymium magnets | + | |
| - | + | ||
| ===== Setup ===== | ===== Setup ===== | ||
| - | + | - Tape the pencil to the top of the lab stand so that the sharpened point points upwards. | |
| - | Place pencil in the vice as shown | + | - Place the plate on top of the pencil. There should be a small divot in the middle so it should stay. |
| - | Attach the pie plate to the pencil by placing its central groove on top of the pencil tip | + | - Ensure the pie plate is balanced. You can slightly bend the edges to adjust the balance. |
| - | Ensure the pie plate is balanced | + | - Hold the magnet about an inch above the surface of the plate and start making circles centered on the plate. |
| - | Hold the magnets about an inch above the surface of the plate and start slowly start making circles along a radius of the pie plate | + | - You should now see the plate slowly begin to rotate in the same direction as the magnet. |
| - | The pie plate will start spinning | + | |
| - | Increase speed as pie plate turns faster | + | |
| - | + | ||
| ===== Notes ===== | ===== Notes ===== | ||
| + | The strength of this effect is mediated by a few things: | ||
| + | * The conductivity of the material. Copper would produce a stronger effect, but aluminum is still fairly conductive. A greater conductivity means the currents set up by the changing magnetic field will be stronger and therefore produce a greater force. | ||
| + | * The strength of the magnetic field (the size of the magnet / the proximity of the magnet). A greater magnetic field will produce a larger change in flux and therefore a greater force. | ||
| + | * The speed of the magnet. A greater speed means there'll be a larger change in flux and therefore a bigger force. | ||
| Line 65: | Line 53: | ||
| </WRAP> | </WRAP> | ||
| <WRAP tablewidth 100%> | <WRAP tablewidth 100%> | ||
| - | | **Location** | ---- | | + | | **Location** | O2 | |
| | **Maker** | Unknown | | | **Maker** | Unknown | | ||
| | **Current State** | Working | | | **Current State** | Working | | ||
demonstrations/5_electricity_and_magnetism/5k_electromagnetic_induction/eddy_currents_in_a_spinning_pie_plate/start.1550187203.txt.gz · Last modified: 2019/02/14 23:33 by 127.0.0.1
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