Announcements Quiz tomorrow (obj. 1-5) Videos due at midnight (no late credit)

Restless Electrons 4.1.2 Transfer of Charge

Conductive Properties of Materials NbTi alloy metals silicon wood rubber sea water pure water HIGH CONDUCTIVITY LOW CONDUCTIVITY LOW RESISTIVITY HIGH RESISTIVITY Good Conductor/ Poor Insulator Allows electrons to flow freely. Good Insulator/ Poor Conductor Strongly resists flow of electrons.

RULE #1 – ONLY ELECTRONS MOVE Charging by Friction Rub two insulators together ELECTRONS move from one to the other One object becomes + the other - RULE #1 – ONLY ELECTRONS MOVE

RULE #2 – GROUNDING MAKES AN Since the Earth is very large it can neutralize: negative objects by ABSORBING electrons positive objects by RELEASING electrons - + - + - - + - + RULE #2 – GROUNDING MAKES AN OBJECT NEUTRAL - - - Grounding Symbol: -

Induction – Negative Rod Induction – movement of charge without contact - RULE #3 – ELECTRONS FLOW TOWARD LESS NEGATIVE/MORE POSTIVE AREAS - - + - - - - - - - - - - - - - - - - - - - - - - 3 + - - + 1 + - - + 2 + - ANIMATE NEXT

Induction – Positive Rod Induction – movement of charge without contact - - RULE #4 – INDUCTION = POLARIZATION - - + - + + + + + + + - - - - - - - - - - 1 + - - + 2 - + 3 + - - + - - ANIMATE NEXT

Conduction – Negative Rod Conduction – movement of charge with contact RULE #5 – CHARGING BY CONDUCTION GIVES SAME CHARGE - - - - - - - - - - - - - - - - - - - - 2 - e- 3 - 1 + - - + ANIMATE NEXT

Conduction – Positive Rod Conduction – movement of charge with contact - - - RULE #5 – CHARGING BY CONDUCTION GIVES SAME CHARGE + + + + + + + + + + - - 1 + - - + 2 + e- 3 + - - - ANIMATE NEXT

The Electroscope UNCHARGED CHARGED - - LEAVES

Induction – Negative Rod - - - - - - - - - - - - - + e- e- 2 + - e- 3 1 - - RULE #4 ANIMATE NEXT

Induction – Positive Rod + + + + + + + + + - - e- e- 1 2 - + e- 3 + + RULE #4 ANIMATE NEXT

Charging by Conduction – Negative Rod - - - - - - - - - - - - e- - e- - 2 - e- 4 e- 3 - 1 5 - - RULE #5 ANIMATE NEXT

Charging by Conduction – Positive Rod + + + + + + + + + e- - e- + 5 3 + 2 - e- + 1 4 e- + + RULE #5 ANIMATE NEXT

Object A is negatively charged and is used to charge object B by conduction. What is the final charge on objects A and B? Object A is negatively charged and is brought near neutral object B without touching it. What is the final charge on objects A and B after it is pulled away? Object A is negatively charged and is used to charge object B by induction. What is the final charge on objects A and B? A small object is tested to determine its charge. What test could be used to prove that the object is positively charged? What test could be used to prove that the object is not charged? A negatively charged rod is brought near a neutral electroscope then removed, what is the reaction of the electroscope leaves? A negatively charged rod is brought near a charged electroscope causing its leaves to diverge. What is the charge on the electroscope?

Object A is negatively charged and is used to charge object B by conduction. What is the final charge on objects A and B? [A -; B -] Object A is negatively charged and is brought near neutral object B without touching it. What is the final charge on objects A and B after it is pulled away? [A -; B=0] Object A is negatively charged and is used to charge object B by induction. What is the final charge on objects A and B? [A -; B +/- (polarized)] A small object is tested to determine its charge. What test could be used to prove that the object is positively charged? What test could be used to prove that the object is not charged? [repelled from + or attracted to -; attracted to + AND -] A negatively charged rod is brought near a neutral electroscope then removed, what is the reaction of the electroscope leaves? [diverge (separate) then converge (combine)] A negatively charged rod is brought near a charged electroscope causing its leaves to diverge. What is the charge on the electroscope? [-]