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Electricity Electric Charge and Static Electricity Electric Current Batteries Electric Circuits Electric Power Electrical Safety Table of Contents Slide 2 Electricity - Electric Charge and Static Electricity Electric Charge Charges that are the same repel each other. Charges that are different attract each other. Slide 3 Electricity - Electric Charge and Static Electricity Electric Force An electric field is a region around a charged object where the objects electric force is exerted on other charged objects. Slide 4 Electricity - Electric Charge and Static Electricity Electric Force An electric field is a region around a charged object where the objects electric force is exerted on other charged objects. Slide 5 Electricity - Electric Charge and Static Electricity Transferring Charge There are three methods by which charges can be transferred to build up static electricity: charging by friction, by conduction, and by induction. Slide 6 Electricity - Electric Charge and Static Electricity Transferring Charge An electroscope can be used to detect the presence of a charge. Slide 7 Electricity Previewing Visuals Before you read, preview Figure 4. Then write two questions that you have about the diagram in a graphic organizer like the one below. As you read, answer your questions. Transferring Static Electricity Q. What are three ways that static electricity can be transferred? A. Charging by friction, charging by conduction, and charging by induction Q. Why does an object become charged? A. An object becomes charged when electrons are transferred from one location to another. - Electric Charge and Static Electricity Slide 8 Electricity Links on Static Electricity Click the SciLinks button for links on static electricity. - Electric Charge and Static Electricity Slide 9 Electricity Lightning Click the Video button to watch a movie about lightning. - Electric Charge and Static Electricity Slide 10 Electricity End of Section: Electric Charge and Static Electricity Slide 11 Electricity - Electric Current Flow of Electric Charges Electric current is the continuous flow of electric charges through a material. Slide 12 Electricity - Electric Current An Electric Circuit An electric circuit is a complete, unbroken path through which electric charges can flow. Slide 13 Electricity - Electric Current Resistance Two factors that affect the resistance of water flowing in a pipe are diameter and length. The diameter and length of a wire also affect resistance in a circuit. Slide 14 Electricity Outlining As you read, make an outline about electric current. Use the red headings for the main ideas and the blue headings for the supporting ideas. Electric Current I.Flow of Electric Charges A.What Is Electric Current? B.Current in a Circuit II.Conductors and Insulators A.Conductors B.Insulators III.Voltage A.Charges Need Energy to Flow B.Voltage C.Voltage Sources IV.Resistance A.Current Depends on Resistance B.Factors That Determine Resistance C.Path of Least Resistance - Electric Current Slide 15 Electricity More on Electric Current Click the PHSchool.com button for an activity about electric current. - Electric Current Slide 16 Electricity End of Section: Electric Current Slide 17 Electricity - Batteries The First Battery Volta built the first electric battery by layering zinc, paper soaked in salt water, and silver. Slide 18 Electricity - Batteries Electrochemical Cells An electrochemical cell is a device that transforms chemical energy into electrical energy. Slide 19 Electricity - Batteries Electrochemical Cells An electrochemical cell in which the electrolyte is a liquid is a wet cell. Slide 20 Electricity - Batteries Electrochemical Cells A dry cell is an electrochemical cell in which the electrolyte is a paste. Slide 21 Electricity Building Vocabulary After you read the section, reread the paragraphs that contain definitions of Key Terms. Use the information you have learned to write a definition of each Key Term in your own words. Key Terms: Examples: electrolyteAn electrolyte is a substance in an electrochemical cell through which current flows. - Batteries chemical energyChemical energy is the energy that chemical compounds store within the compounds. chemical reactionA chemical reaction is a process in which substances change into other substances with different properties than the original substances. electrochemical cellAn electrochemical cell is an electrical device that changes chemical energy into electrical energy. Key Terms: Examples: electrode terminal battery wet cell dry cell A metal in an electrochemical cell that is covered with electrolyte is called an electrode. The electrode part that sticks up above the electrolyte is called the terminal. A battery is a series of electrochemical cells. A wet cell is an electrochemical cell that has liquid as its electrolyte. A dry cell is an electrochemical cell that has paste as its electrolyte. Slide 22 Electricity End of Section: Batteries Slide 23 Electricity Decimals When calculating voltage, you often use decimals. When you multiply two decimals, the number of decimal places in the product is the sum of the number of decimal places in each decimal you multiply. If a circuit has a resistance of 30.5 ohms and a current of 0.05 amps, what is its voltage? - Electric Circuits Slide 24 Electricity Decimals Practice Problem Use Ohms law to calculate the voltage of a circuit with a resistance of 15.2 ohms and a current of 0.10 amps. 1.52 volts - Electric Circuits Slide 25 Electricity Calculating Resistance The brake light on an automobile is connected to a 12-volt battery. If the resulting current is 0.40 amps, what is the resistance of the brake light? Read and Understand What information are you given? Battery Voltage = 12 V Current = 0.40 A - Electric Circuits Slide 26 Electricity Calculating Resistance The brake light on an automobile is connected to a 12 volt battery. If the resulting current is 0.40 amps, what is the resistance of the break light? Plan and Solve What quantity are you trying to calculate? The resistance of the brake light What formula contains the given quantities and the unknown quantity? Resistance = Voltage/Current Perform the calculation. Resistance = 12 V/0.40 A = 30 - Electric Circuits Slide 27 Electricity Calculating Resistance The brake light on an automobile is connected to a 12-volt battery. If the resulting current is 0.40 amps, what is the resistance of the brake light? Look Back and Check Does your answer make sense? The answer makes sense because you are dividing the voltage by a decimal. The answer should be greater than either number in the fraction, which it is. - Electric Circuits Slide 28 Electricity Calculating Resistance Practice Problem In a circuit, there is a 0.5-A current in the bulb. The voltage across the bulb is 4.0 V. What is the bulbs resistance? 8.0 (4.0 V 0.5 A) - Electric Circuits Slide 29 Electricity Calculating Resistance Practice Problem A waffle iron has a 12-A current. If the resistance of the coils is 10 , what must the voltage be? 120 V (12 A X 10 ) - Electric Circuits Slide 30 Electricity - Electric Circuits Features of a Circuit Simple symbols are used to diagram a circuit. Slide 31 Electricity - Electric Circuits Series Circuits In a series circuit, there is only one path for the current to take. Slide 32 Electricity - Electric Circuits Parallel Circuits In a parallel circuit, there are several paths for the current to take. Slide 33 Electricity Series and Parallel Circuits Activity Click the Active Art button to open a browser window and access Active Art about series and parallel circuits. - Electric Circuits Slide 34 Electricity Comparing and Contrasting As you read, compare and contrast series circuits and parallel circuits in a Venn diagram like the one below. Write the similarities in the space where the circles overlap and the differences on the left and right sides. Series CircuitParallel Circuit Only one path for current to take Unbroken path that has a current Several paths for current to take - Electric Circuits Slide 35 Electricity End of Section: Electric Circuits Slide 36 Electricity - Electric Power Electric Power The rate at which energy is transformed from one form to another is known as power. Power is measured in watts (W). Slide 37 Electricity Calculating Power A household light bulb has about 0.5 amps of current in it. Since the standard household voltage is 120 volts, what is the power rating for this bulb? Read and Understand What information have you been given? Current= 0.5 A Voltage= 120 V - Electric Power Slide 38 Electricity Calculating Power A household light bulb has about 0.5 amps of current in it. Since the standard household voltage is 120 volts, what is the power rating for this bulb? Plan and Solve What quantity are you trying to calculate? The power of the light bulb = ? What formula contains the given quantities and the unknown quantity? Power = Voltage X Current Perform the calculation. Power = 120 V X 0.5 A Power = 60 W - Electric Power Slide 39 Electricity Calculating Power A household light bulb has about 0.5 amps of current in it. Since the standard household voltage is 120 volts, what is the power rating for this bulb? Look Back and Check Does your answer make sense? The answer is reasonable, because 60 W is a common rating for household light bulbs. - Electric Power Slide 40 Electricity Calculating Power Practice Problem A flashlight bulb uses two 1.5-V batteries in series to create a current of 0.5 A. What is the power rating of the bulb? 1.5 W (3.0 V X 0.5 A) - Electric Power Slide 41 Electricity Calculating Power Practice Problem A hair dryer has a power rating of 1,200 W and uses a standard voltage of 120 V. What is the current through the hair dryer? 10 A (1,200 W 120 V) - Electric Power Slide 42 Electricity Question Answer Asking Questions Before you read, preview the red headings. In a

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