Section1
A. Electricity beginsat the atomic levelwhereprotons and electrons
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Note-taking Worksheet.
haveelectriccharge.
1. Protons carry a positivechange.
2. Electronscarry a ne~ativecharge.
3. l.Qn§.form when atomsloseor gain electronsand becomepositivelyor negativelycharged.
4. Electronscan movefrom objectto object;static charie is the buildup of electriccharge
on an object.
5. A flow of chargecanbe causedby ions moving in a solution.
B. All objectsexertan electricforceon eachother;it canbeattractiveor repulsive.
1. Like chargesrepel,unlike chargesattract.
2. Electric chargesexerta force on eachother at a distancethrough an electric field which
existsaround everyelectriccharge
C. Insulator-material which doesnot allow electronsto moveeasily;
conductor-material that allowselectronsto moveeasily;metalsarethe bestconductors
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D. Electric discharse--rapid movementof excesschargefrom one placeto another;lightning is
an electricdischarge.
E. Grounding-provides a pathwayto drain excesschargeinto the Earth; lightning rods provide
grounding for manybuildings.
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DISCUSSION
QUESTION:
What is static charge?Buildup of electric chargeon an object
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T2
Electricity
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Section2
ElectricCurrent
A. Electric current - flow of chargethrough a conductor
1. In solidsthe flowing chargesareelectrons;in liquids the flowing chargesarepositiveor negativeions.
a. Circuit-closed conductingloop through which electriccurrentscontinuouslyflow
b. Current~
cando work in an electricdevice;flow carrieselectricalenergythrough wire.
c. Voltage-measure of how much electricenergya battery canprovide
d. Electronsmovein a circuit and havemillions and millions of collisions.
2. The voltageof a battery dependson the amount and type of chemicalsusedto createthe
chemicalreactionsin a battery.
3. Batteries
Qk when the original chemicalsare usedup and the chemicalreactionsin the
~ttery stop.
B. Resistance-measureof how difficult it is for electronsto flow through a material
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1. Insulators generally have much high.e:rresistancethen conductors.
2. The amount of electricenergythat is convertedinto thermal energyincreasesasthe
resistanceof wire increases.
3. The length and diameterof a wire affectelectronflow.
DISCUSSIONQUESTION:
Why do batteries die? The chemicals providing the source of chemical reactions are used up.
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Section3
ElectricCircuits
A. The amount of current is determinedby the voltagesuppliedby a battery and the resistanceof
the conductor.
1. As the resistancein an electriccurrent increases,
the current in the circuit decreases.
2. Ohm's law-current = voltage/resistance
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3. When the voltagein a circuit increases,the current increases.
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B. There are ~
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kinds of basic circuits: seriesand parallel.
circuit hasonly one path for the electriccurrent to follow-if path is broken,the
current will no longer flow and all devicesin the circuit stopworking.
2. A p;arallelcircuit hasmore than one path for the electriccurrent to follow.
ElectricityT3
C. For safety,circuits in homesand buildings have~
or circuit breakersthat limit the amount
of current in the wiring.
D. Electric I?ower-rate at which an applianceconvertselectricalenergyto anotherform of energy
1. Power= current x voltage
2. Theunit of poweris the~.
3. Electric companieschargecustomersfor the number of kilowatt-hours they usein a month.
E. Electricity canbe dan~erous.
1. Current can enteryour body and shockyou when your body accidentallybecomespart of
an electriccircuit.
2. Lightning canbe deadly;if caughtoutdoorsnearlightning usea lightning-safety
position-squat on the balls of the feet with handson knees.
DISCUSSION
QUESTION:
How doesthe body receivean electricshock?The body becomespart of an electric circuit; ions in
the body conduct charge.
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T4 Electricity