Static Electricity Static Electricity

Electrostatics All matter is made of atoms which are composed of protons and neutrons in the nucleus and electrons that are positioned around the nucleus in electron shells

Oxygen Molecule

Electrons are negatively charged and are weakly bound to the atom therefore electrons are easily added to and removed from atoms; these occurrences are the focus of static electricity Substances with an excess of electrons are negatively charged Substances with a deficiency of electrons are positively charged

The number of electrons that surround a nucleus will determine whether or not an atom is electrically charged or electrically neutral: 1. electrically neutral atoms contain an equal number of protons and electrons 2. positively charged atoms (cation) contain more protons than electrons 3. negatively charged atoms (anions) contain more electrons than protons

Charge interactions occur because electrons have been transferred from one object to another, but electric charge is conserved meaning no charge is created or destroyed, just transferred meaning no charge is created or destroyed, just transferred

–A positively charged object and a negatively charged object exert an attractive influence on each other –Two objects of like charge will repel each other –Any charged object will have an attractive force with a neutral object How Do Variously Charged Objects Interact with One Another?

Methods used for Charging Objects 1.Friction: charging is due to two objects rub against each other or when an object moves through another object Ex: rubbing your feet over the carpet Ex: a car driving through the air (Do you get shocked more getting out of your car in the summer or the winter?)

2.Contact/Conduction: when two objects come into physical contact with one another

3.Induction: charging an object by bringing it near another charged object; no physical contact

Materials that gain a positive (+) electrical charge (or tend to give up electrons) Dry human 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 Human hair "Flyaway hair" is a good example of having a moderate positive (+) charge Nylon Wool Lead A surprise that lead would collect as much static electricity as cat fur Cat fur Silk Aluminum Gives up some electrons Paper

Materials that are relatively neutral Cotton Best for non-static clothes Steel Not useful for static electricity

Materials that gain a negative (−) electrical charge (Tend to attract electrons) Wood Attracts some electrons, but is almost neutral Hard rubber Some combs are made of hard rubber 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 Wrap You can see how Saran Wrap will stick to things Polyethylene (like Scotch Tape) Pull Scotch Tape off surface and it will become charged Vinyl (PVC) Many electrons will collect on PVC surface Teflon Greatest tendency of gathering electrons on its surface and becoming highly negative (−) in charge