Electrostatics Physics

A. Definition  The study of electrical charge that can be collected and held in one place

B. Examples of Static Charge  Socks in a dryer  Sliding feet on carpet  Rubbing a balloon

C. Electric states of Matter  Neutral: negative charge = positive charge  Negatively charged: excess of electrons (e - )  Positively charged: deficiency of e -

Special Note  e - is responsible for understanding electrical phenomena

D. Rules of Charge  Like charges repel  Opposite charges attract  Charge is conserved

Classes of Matter A. Conductors CrystalLattice: e - flow freely

Conductor 2. Description  material that readily transfers charge  e - are free to move around in the crystal lattice (sea of e - )

Conductor  3. Examples:  Metals  Water  Earth (best)  Lightening strike Struck by lightning Roy Sullivan Lightening strike Struck by lightningRoy Sullivan Lightening strike Struck by lightningRoy Sullivan

B. Insulators  1. Description: e - are tightly bound to nuclei and will not readily transfer  2. Examples: plastic, wood, glass, rubber, paper

Semi-Conductors  1. e - can move more freely than in an insulator, but not as easily as conductors  2. Examples: Silicon, Germanium

III. A. Induction  1. How is it done?: Bring a charged object near another uncharged object (no contact)  2. What occurs?: e - are either attracted or repelled from the charged object

3. Diagram

Induction 4. Resulting Charge  Resulting Charge:  Opposite of charging object (temporary)  Overall charge is still neutral

B. Conduction  1. How? Touch charged object to another object  2. What occurs? e - are transferred

Conduction

Conduction  4. Resulting Charge: same charge as charging object and charge is permanent Video : conduction and induction

Grounding  Process of removing excess charge from an object by transfer of e - to a larger object  Ex.: middle prong on wall outlet

1. Mike is investigating the charge on several objects and makes the following observations: C attracts B, D repels C, E attracts D and repels F, F attracts A; If A is negatively charged and B is neutral, what can Michael conclude about the charge of C, D, E, and F? F is positive, E is positive, D is negative, and C is negative

2. A metal sphere is electrically neutral. It is touched by a positively charged metal rod. As a result, the metal sphere becomes charged positively. Which of the following occur during the process? (multiple answers) a. The metal sphere gains some protons. b. Electrons are transferred from the sphere to the rod. c. The metal sphere loses electrons. d. The overall charge of the system is conserved. e. Protons are transferred from the rod to the sphere.

3. A metal sphere is electrically neutral. A positively charged metal rod is brought very near to it without actually touching it. The metal sphere will now be attracted to the metal rod because.. a.The metal sphere temporarily behaves as if it is negative. b.The metal sphere temporarily behaves as if it is positive. c.The metal sphere has now become permanently charged negative. d.The metal sphere has now become permanently charged positive.

4. You have built up a strong negative charge on your body by dragging your feet across a shaggy carpet. When you reach the other side of the room where you little brother is sitting you decide to touch him on the ear. You hear a satisfying “gizzouch” as he screams out in surprise. This electrostatic shock occurred because of a.Induction caused your brother to become negatively charged like you. b.Conduction cause your brother to become positively charge. c.Grounding caused your negative charges to travel through his body.

Extra Help  The physics classroom The physics classroom The physics classroom  Bill Nye the science guy Bill Nye the science guy Bill Nye the science guy