SLIDE 13 1/29/2018 13
http://www.school-for-champions.com/science/static_materials.htm
Becom e positive in charge
The following m aterials will tend to give up electrons when brought in contact with
- ther materials. They are listed from those with the greatest tendency to give
electrons to those that barely give up electrons. Dry hum an skin Greatest tendency to giving up electrons and becoming highly positive (+ ) in charge Leather Rabbit fur Fur is often used to create static electricity Glass The glass on your TV screen gets charged and collects dust Hum an hair "Flyaway hair" is a good example of having a moderate positive (+ ) charge Nylon W ool Lead A surprise that lead would collect as much static electricity as cat fur Cat fur Silk Alum inum Gives up som e electrons Paper
Neutral
There are very few m aterials that do not tend to readily attract or give up electrons when brought in contact or rubbed with other m aterials. Cotton Best for non-static clothes Steel Not useful for static electricity
Becom e negative in charge
The following materials will tend to attract electrons when brought in contact with
- ther materials. They are listed from those with the least tendency to attract
electrons to those that readily attract electrons. W ood Attracts som e electrons, but is almost neutral Am ber Hard rubber Som e combs are made of hard rubber Nickel, Copper Copper brushes used in Wimshurst electrostatic generator Brass, Silver Gold, Platinum It is surprising that these metals attract electrons almost as much as polyester Polyester Clothes have static cling Styrene ( Styrofoam ) Packing material seems to stick to everything Saran W rap You can see how Saran Wrap will stick to things Polyurethane Polyethylene ( like Scotch Tape) Pull Scotch Tape off surface and it will become charged Polypropylene Vinyl ( PVC) Many electrons will collect on PVC surface Silicon Teflon Greatest tendency of gathering electrons on its surface and becom ing highly negative (-) in charge
Triboelectric Series
An effort to reconstruct Millikan's "exemplary" experimental thinking revealed serious discrepancies between Millikan's notebooks and his published "raw" data (Holton, 1978). The numerous notes which are scattered across the pages cast further doubt
This is almost exactly right & the best one I ever had!!! [20 December 1911] Exactly right [3 February 1912] Publish this Beautiful one [24 February 1912] Publish this surely / Beautiful !! [15 March 1912, #1] Error high will not use [15 March 1912, #2] Perfect Publish [11 April 1912] Won't work [16 April 1912, #2] Too high by 1½% [16 April 1912, #3] http://www1.umn.edu/ships/ethics/millikan.htm
