Static electricity occurs when objects become electrically charged through the transfer of electrons. Charging occurs when two materials are rubbed together, causing electrons to move from one material to the other. This leaves one material with an excess of electrons and a negative charge, and the other material with a deficit of electrons and a positive charge. The electric charges remain on the surface of the objects until they are given a path to ground or neutralize each other through contact or discharge.

1. Static Electricity

2. all matter is made of atoms atoms contain smaller particles: protons , neutrons and electrons some of these particles have an electric charge: Atomic Structure & Electric Charge

3. orbiting the nucleus negative (-) electron nucleus no charge (0) neutron nucleus positive (+) proton Location Electric Charge Particle

4. If an object has more electrons than protons, it is negatively charged. Electric Charge # protons: 8 # electrons: 12 # protons < # electrons therefore, overall charge = negative

5. if an object has more protons than electrons, it is positively charged Electric Charge # protons: 8 # electrons: 5 # protons > # electrons therefore, overall charge = positive

6. If an object has an equal number of protons and electrons, the object is neutral Electric Charge # protons: 8 # electrons: 8 # protons = # electrons therefore, overall charge = neutral

7. Electric Charge + — Law of attraction: opposite charges attract

8. Electric Charge Law of repulsion: like charges repel + — + —

9. Electric Charge A charged object and a neutral object will attract each other 0 0 + —

10. Electrons can be transferred from one object to another. For example, a neutral or positively charged object will become negatively charged if it gains electrons. Electric Charge

11. Similarly, a neutral or negatively charged object will become positively charged if it loses electrons. Electric Charge

12. Only electrons (negative charges) are capable of moving from one object to another! Protons ( positive charges) stay in place. Electric Charge

13. Different substances have different abilities to hold on to electrons the tendency of a substance to hold on to the electrons is called electron affinity Electron Affinity

14. Electron Affinity human skin rabit fur acetate glass human hair nylon wool cat fur silk paper cotton wood amber rubber balloon vinyl polyester ebonite + - tendency to lose electrons tendency to gain electrons

15. Conductivity is the ability of materials to allow electrons to move freely Materials that hold on to their electrons and do not allow them to move easily are called electrical insulators Materials that allow electrons to change positions are called conductors Conductors & Insulators

16. Insulators In an insulator, the electrons (-) are bound tightly to the nuclei (+) so they resist movement + — + — + — + — + — + — + —

17. Common Insulators

18. Conductors In a conductor, the electrons are not as tightly bound to the nuclei and can therefore move away from the nuclei + — + — + — + — + — + — + —

19. Common Conductors

20. The electric charge that builds up on the surface of an object is called a static charge The charges are “static” because they remain in one location on the surface of the object until they are given a path to escape Static Electricity

21. Static Electricity and Friction All solid materials are charged by the transfer of electrons When two objects rub together, the force of friction can remove electrons from one object and transfer them to the other object

22. As one object loses electrons, the other object gains them Static Electricity and Friction

23. New electrons are not being created , they are just being rearranged Static Electricity and Friction

24. Static Electricity