Presentation Outline Review Previous Day Distribution of Charges in a Neutral Conductor (Homework) Distribution of Charges in a Neutral Insulator (Homework) Charging a Conductor by Touching Inducing a Charge on a Conductor (Polarization) Demo: Comb and paper / Rod and wood Attraction between neutral conductor and charged object Attraction between neutral insulator and charged object Practice
Exit Quiz from Yesterday What is the difference between a conductor and an insulator? What kind of charge is not able to flow freely in a conductor? If an object acquires a positive charge, did it gain protons or lose electrons? How do you know? Why are cars safe in a lightning storm? What does it mean for an object to be electrically polarized?
Let’s go back to the polarized neutral object…
If you could take a guess, would the rod and ball be attracted to or repelled by each other? Why do you think so?
If you could take a guess, would the rod and ball be attracted to or repelled by each other? Why do you think so? Negative and Positive are attracted!
If you could take a guess, would the rod and ball be attracted to or repelled by each other? Why do you think so? If we switched to a positively-charged rod, would they rod and ball attract or repel? Negative and Positive are attracted!
If you could take a guess, would the rod and ball be attracted to or repelled by each other? Why do you think so?
A charged object will always attract a neutral conductor! If you could take a guess, would the rod and ball be attracted to or repelled by each other? Why do you think so? This works for any polarized neutral conductor. A charged object will always attract a neutral conductor! Positive and Negative are attracted!
So, charged objects attract conductors… What about attracting insulators?
So, charged objects attract conductors… What about attracting insulators?
So, charged objects attract conductors… What about attracting insulators?
So, charged objects attract conductors… What about attracting insulators?
Time for the “magic” wand! So, charged objects attract conductors… What about attracting insulators? Time for the “magic” wand!
Sticky Balloons https://phet.colorado.edu/en/simulation/balloons
Charged Objects Also Attract Neutral Insulators! When a charged object is brought near an insulator, the charges in the insulator can shift back and forth a little. For example, a negatively charged plastic rod causes a slight shifting of charge within the molecules of the neutral wood. The negative charges shift so that they are farther from the rod. The wood has an excess positive charge near the rod and so feels an attraction. http://regentsprep.org/Regents/physics/phys03/ainsvscon/default.htm
Charged Objects Also Attract Neutral Insulators! When a charged object is brought near an insulator, the charges in the insulator can shift back and forth a little. For example, a negatively charged plastic rod causes a slight shifting of charge within the molecules of the neutral wood. The negative charges shift so that they are farther from the rod. The wood has an excess positive charge near the rod and so feels an attraction. http://regentsprep.org/Regents/physics/phys03/ainsvscon/default.htm
Charged Objects Also Attract Neutral Insulators! Negatively Charged
Charged Objects Also Attract Neutral Insulators! Negatively Charged
Charged Objects Also Attract Neutral Insulators! Negatively Charged
Charged Objects Also Attract Neutral Insulators! Negatively Charged
Charged Objects Also Attract Neutral Insulators! Negatively Charged
Charged Objects Also Attract Neutral Insulators! Negatively Charged
Charged Objects Also Attract Neutral Insulators! Negatively Charged
Charged Objects Also Attract Neutral Insulators! Negatively Charged
Charged Objects Also Attract Neutral Insulators! Negatively Charged
Charged Objects Also Attract Neutral Insulators! Ouch! That’s gonna leave a scar! Negatively Charged
In Conclusion… Charged Objects Attract Neutral Objects ALWAYS Charged objects can “polarize” a neutral conductor—where the electrons can move freely—and become attracted to the neutral object. Charged objects can “shift” the charges in a neutral insulator—where electrons cannot move freely—and become attracted to the neutral object.
Practice!