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25 Cards in this Set
- Front
- Back
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Static Charge |
Electric charge @ rest |
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Discharge |
Charge Lost |
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Electrostatics |
Study of static electric charge |
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Law of Electric Charges |
Like charges repel and unlike charges attract |
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Induced charge separation |
No electrons transferred but = still attracted to + or - |
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Charging by friction |
2 objects rubbed together |
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Charging by induction |
Objects chafed w/o touching |
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Insulator |
Electrons tightly bound to atom no transfer |
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Conductor |
Electrons can flow freely from atom to atom |
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Grounded |
Conductor brings extra electrons from object to earth (neutralizes object) |
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Van de Graaff generator |
Separates large quantities of electric charge, used to research static electricity |
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Electroscope |
Determines presence of electric charges ( & separates - & + top and bottom) |
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Electric force |
Force btw charges (push or pull) |
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Coulomb's Law |
Strength of electric force increases with increase of electric charges and decreases with increase in distance |
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Coulomb |
Unit of size of electric charge |
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Four Key Ideas |
-static electric charges can build up on objects -objects become charged from friction, conduction, and induction -an electric force btw static charges can either attract or repel them -the discharge of static electricity in the form of lightning can be dangerous, but static electricity also has useful applications |
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Franklin's Experiment |
He demonstrated lightning his a form of electricity by flying a kite with a metal rod at the tip and a metal key attached to the string in a thunderstorm. Electricity from thunder clouds travelled first to the metal tip, then down to the key held by a silk ribbon |
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Franklin's Experiment |
He demonstrated lightning his a form of electricity by flying a kite with a metal rod at the tip and a metal key attached to the string in a thunderstorm. Electricity from thunder clouds travelled first to the metal tip, then down to the key held by a silk ribbon |
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Charges |
-some objects can keep a static charge a long time, especially inside in winter, but eventually all static charge will be discharged - objects become negatively charged when they overall have a greater negative charge (more electrons than protons in total) than positive charge -objects become positively charged when they overall have a greater overall positive charge than negative charge (more protons than electrons in total) |
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Franklin's Experiment |
He demonstrated lightning his a form of electricity by flying a kite with a metal rod at the tip and a metal key attached to the string in a thunderstorm. Electricity from thunder clouds travelled first to the metal tip, then down to the key held by a silk ribbon |
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Charges |
-some objects can keep a static charge a long time, especially inside in winter, but eventually all static charge will be discharged - objects become negatively charged when they overall have a greater negative charge (more electrons than protons in total) than positive charge -objects become positively charged when they overall have a greater overall positive charge than negative charge (more protons than electrons in total) |
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Electrostatic series |
Some materials are more likely to gain electrons than others and some are more likely to lose electrons than others. In the list top is most likely to gain and bottom most likely to lose, so if the object at the top and the object at the bottom came in contact, the one from the bottom would give its electrons to the one at the top |
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How does lightning work? |
Water droplets in a cloud bounce off each other, some becoming positive, others negative. The positive go to the top while the negative go to the bottom (separation of charge). The negative droplets are attracted to the negative in the Earth. The attraction becomes so strong, a pathway is made in the air that conducts the negative electrons down to the earth. The air is excited and heated. The air where the electrons lights up and expands, causing a massive sound wave (thunder and lightning) |
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Semi conductors |
Substances that allow electrons to flow from one atom to another with some resistance |
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Most important |
ONLY ELECTRONS MOVE- protons stay in one place. So if a - rod is brought near = ball, protons stay & electrons leave. If there is a positive charge in an electroscope, when you ground it, the positive stays in place but electrons flow up from earth into electroscope |
