Like Charges Attract

• D+10+25

diagram for demo

A soda can is charged negatively using the cat fur/teflon rod. When an oppositely charged rod (ebonite/plastic) is brought near, the can begins to roll towards the rod as expected. However, when the teflon rod is brought near, the can still rolls towards the rod. This is due to the electrically conductive nature of the can. The rod will repel the charges that were placed on the can and create a positively charged environment on the near surface. So even though the can is net negative, the induced dipole that is created results in a net attraction and the can rolls towards the rod.

Related Demos


D+10+11 Alternate charge resides on outside of conductor D+10+45 Polarization of can causes rolling D+10+5 Vector arrows to show electric field and particle motion D+10+0 Electric fields: Lines of force shown on an OHP. D+10+2 Transparency: Mapping of an electric field. D+10+4 Pith balls on thread, with positive and negative charged rods. D+10+6 Attraction and repulsion of charged styrofoam balls. D+10+8 Braun and Leaf electroscopes. D+10+9 Discharging an electroscope through ionization D+10+10 Faraday's ice pail: Charge induced on the outside of a pail. D+10+12 Charge resides on the outside of a conductor. D+10+13 Faraday cage: blocks signal from portable radio D+10+14 Charging an electroscope by induction. D+10+16 Separation of charge using electrical tape and an electroscope. D+10+18 Electrophorous: Cat fur on teflon, acetate on lucite. D+10+20 Van de Graaff generator. D+10+22 Wimshurst machine, large or small. D+10+24 Electrostatic pinwheel:Van de Graaff makes pinwheel spin. D+10+26 Various Leyden jars to show. D+10+28 Electrostatic doorbell: Ball bangs between charged plates. D+10+30 Kelvin water drop electrostatic charge generator. D+10+35 Electric field created by Van de Graff splits ions in flame D+10+40 Applet: Charges and Fields D+10+45 Applet: Electric Field Hockey D+10+50 Applet: Electric Field of Dreams D+10+55 Applet: John Travoltage D+10+60 Applet: Balloons and Static Electricity D+10+65 Applet: 3D Electrostatic Field Simulation D+10+75 Applet: Field and potential produced by point charges D+10+80 Applet: Electrostatics Visualizations - The Charged Metal Slab D+10+85 Applet: Electric Field D+10+90 Electrostatics Index D+10+95 Applet: Electrostatics Simulation D+10+100 Applet: 2-D Electrostatic Field Simulation