Presentation Transcript

1. Warm Up What do you know about electric charge? Define it and give at least 2 examples.

   Monday, April 21, 2014 Physics

   Standard: Students know charged particles are sources of electric fields and are subject to the forces of the electric fields from other charges. Objective: SWBAT understand the electric force through problem solving. Agenda Warm Up Stamp HW Check Science Fair Summaries Profile of Electric Force Electric Force Activity. Homework EL#1
2. Warm Up What is the net charge of 9 protons combined with 6 electrons?

   Tuesday, April 22, 2014 Physics

   Standard: Students know charged particles are sources of electric fields and are subject to the forces of the electric fields from other charges. Objective: SWBAT draw the electric field lines of different electric charges. Agenda Warm Up Review HW Finish Electric Force Activity Electric Fields Homework P.2 EL #1 P3,4,6,7 EL#2
3. Warm Up Find the electric force between two charges 10 m away if both charges are 2.6x10-8C. Do they attract or repel?

   Wednesday, April 23, 2014 Physics

   Standard: Students know charged particles are sources of electric fields and are subject to the forces of the electric fields from other charges. Objective: SWBAT finalize their Science Fair Topic Agenda Warm Up Review EL#2 Turn in Activities & Demonstrate Van de Graff Generator Introduce Next Steps for Science Fair Research & Complete Topic Selection Homework Begin Research Paper EL #2

4. Thursday, April 24, 2014Physics

   Standards: Students know how to solve problems involving Ohms Law Objective: SWBAT solve electric circuits problems. Agenda: Warm Up Current & Voltage Notes Current & Voltage practice Warm Up Find the electric field created by a 3x10-6C charge at a distance of 1000 m. Homework EL#3
5. Warm Up Find the total electric charge of 4.6 x1012protons

   Friday, April 25, 2014 Physics

   Standards: Students know how to solve problems involving Ohms Law Objective: SWBAT understand Ohms law and solve problems with resistors in series. Agenda Warm Up Stamp EL#1-EL#3 Ohms Law & Series Circuits Begin EL#4 Homework EL#4
6. Profile of Electric Force What is it? The Force of attraction or repulsion between unlike or like electric charges. Fe(-on+) + Fe(+on-) - Fe(+on+) + + Fe(+on+) Equation Fe(-on-) - - Fe(-on-) k is Coulomb’s Constant 9x109 Nm2/C2, q is charge measured in Coulombs ( C ) r is distance between the two charges measured in meters (m) Vector or Scalar? Vector The smallest positive charge is an proton at + 1.6x10-19C The smallest negative charge is an electron at -1.6x10-19C Units: Newton’s N (kgm/s2) Type of Force: Field Force: Acts from a distance.
7. Electric Force Activity Step 1: Place each cylinder at the corner of the table. Give each cylinder a number. Step 2: Find the total electric charge inside each cylinder. (small marbles and beads are electrons, large marbles and golf balls are protons) Step 3: Find the electric force between 3 sets of charges. Example: cylinder 1 & 2, then 1&3, then 1&4. Step 4: Draw a diagram of each set of charges that you used to find Electric Force. Electric Fields: Step 5: Draw an electric Field diagram for Each Cylinder of charge. (Remember larger charges need to have more lines than smaller charges) Step 6: Calculate the Electric Field due to each cylinder 1 cm away. Label that spot on your diagram.
8. EL#1 Electric Force q1=2C q2=-4C r=10 m k=9x109Nm2/C2 F=? b. q1=1x10-6C q2=-2x10-4C r=100 m k=9x109Nm2/C2 F=? C. q1=10 C q2= 5 C r=? k=9x109Nm2/C2 F=20,000 N Find the total electric charge of 20 electrons. If the group of 20 electrons from problem one encounter a negative electric charge of 3x10-12C 10 m away. Find the electric Force between them. From 2, will the 20 electrons apply more force than the -3x10-12C charge, less force, or the same amount of force? A rod with a 3x10-4 C charge is placed 0.10 m from a ballon with a charge of -1x106C? Will the balloon be attracted or repelled from the rod? What is the electric force between the rod and the balloon?
9. Profile of Electric Field Symbol: E Equation: E=kq/r2 Units: N/C Vector or Scalar: Vector If you place a charge inside an electric field of another charge then you can just use Coulomb’s Law to find the Electric Force Between the Charges.
10. Electric Fields of Like & Unlike Charges Draw what you think the electric field diagram would look like for 2 electrons.
11. Drawing Electric Field Lines Rules: Electric Field Lines are always perpendicular to the electric charge. Electric Field Lines always point towards a negative charge and away from a positive charge. Electric Field Lines closer together represent a stronger Electric Field. Electric Field lines further apart represent a weaker electric Field.
12. EL #2 c. E=4x106 N/C k= 9x109Nm2/C2 q= ? r=6 m 1. Make an Electric Field Diagram of a proton 2. Make an Electric Field Diagram of an electron 3. Make an Electric Field Diagram of a proton next to an electron. 4. On your proton diagram from #1, find and label the electric field 6 cm away. 5. On your electron diagram from #2, find the label the magnitude of the electric field 10cm away. E=? k= 9x109Nm2/C2 q= 2C r=4m b. E=? k= 9x109Nm2/C2 q= 4x10-8C r=2m
13. Symbols, units and equations Study Guide Equations: Electricity Energy & Momentum Cons. of Mom. piT=pFT Impulse=Δp=FΔt p=mv Constant Velocity Forces Constant Acceleration ag=-9.8m/s2 The Two equations of Motion for Falling Objects The Two equations of Motion 1. 2.
14. Group Lab Write Up Rubric
15. Circuits – Electric Current I Current = charge/time, I=Q/t, Current=Moving charges, think of it as being like velocity. The smallest unit of charge is the charge of an electron and a proton. 1 electron has a charge of -1.6x10-19Coulombs. 1 proton has a charge of 1.6x10-19 Coulombs So the units of Electric Current is Coulombs/second or Ampere’s (A) - - - - - - - - +
16. Circuits - Voltage You may hear it referred to as potential difference as well. They refer to the same thing. *V=Ue/q=Voltage= Potential Energy / electric charge. *We measure Voltage in Volts (V) or J/c. + charges are attracted to - charges. This gives them kinetic energy Voltage is the energy that each of the trillions of charges have because of the electric force. By taking little bits of energy to a lot of charges, we can power big things. The light uses up some of the kinetic energy of the electrons flowing through the wire. + + + + + + Energy Energy Energy Energy Energy Energy V When + and – meet, no more energy. + + + + + Energy Energy Energy Energy Energy
17. EL#3:Electric Current/Voltage b. I=? q=6C t=12 s c. Ue=2000 J q=3x10-6 C V=? 20,000 electrons q=? . If a power source works at 240 V, and can produce 20,000 Joules of electrical energy, how much charge is there in the power source? Draw and label a simple circuit with a voltage of 10V, and a resistance of 50Ω? A battery is powered by an 9 V battery. If 2x10-3 C of charge is released from the battery into the circuit, find the amount of energy released by the battery. - What is the current running through a coil if 42 Coulombs of charge flows through the marked spot every 10 seconds? How much charge is flowing through a wire in 50 seconds if it has a current of 0.5 Amps? If you have 2000 protons flow through a wire in 20 seconds, what is the current through the wire? - - - - -
18. Circuits-Resistance Resistance is like friction. It drains energy. The light below is using up some of the energy being carried by the electrons. The energy not used up by the resistor is wasted. The + charge goes to the shorter negative side of the battery and the 2 charges neutralize. A light bulb has resistance. Instead of drawing light bulbs, appliances, or the device you want to plug in, we can use to symbolize them. We use to symbolize voltage. Resistance is measured in Ohms (Ω). The units of resistance were named after the scientist who discovered that I=V/R which is called Ohms Law. + + + + + + Energy Energy Energy Energy Energy Energy V + + + + + Energy Energy Energy Energy Energy
19. Resistors in Series When resistors are in Series, energy from the battery travels through the wire carried by electric current. After going through each resistor the current loses some of its energy. To find the total resistance of multiple resistors in series: Requivalent=R1+R2+…Rn Req=2Ω+1Ω=3Ω I 2Ω V + + + + + + Energy Energy Energy Energy Energy Energy I=V/Req=9V/3Ω=3A 9V + + + 1Ω Energy Energy Energy
20. EL #4 Ohms Law & Series Circuits d. Series Circuit R1=2Ω R2=4Ω R3=6Ω R4=8Ω Req=? Series Circuit R1=5Ω R2=10Ω Req=? a. I=? V=12 V R= 20Ω b. I= 2x10-3A V=50 V R= ? 1. If a simple circuit is hooked up to a light bulb with an unknown resistance, what would the resistance of the light bulb be if its power source produced 120 V and 0.5 A of current? 2. You want to work a blender which has a resistance of 120Ω, but you only have a 9V battery. If the blender requires 1.2 A of current to run, will you be able to use your battery? Find the Current in Diagram A Find the Resistance in Diagram B Find the equivalent Resistance of the series circuit in Diagram C Find the equivalent Resistance of the series circuit in Diagram D A I 3Ω D 2Ω 0.5A 8V B 7Ω 8V 0.5A 3Ω C R 6Ω 0.8A 8V 7Ω 8V
21. EL#4 Ohms Law & Series Circuits 1. Find the total Resistance of a series circuit with 3 resistors, each being 4Ω. Find the total Resistance of the following circuit. 4Ω 2Ω Find current of a series circuit with a 10Ω and 6Ω resistor being driven by an 8V battery. Find the voltage of a battery that drives 2A of current through a 3Ω and a 9Ωresistor. Find the Voltage of the battery powering the circuit to the right. For the battery on the right, find out how much the voltage drops as the current passes through each resistor. I 10V 6Ω 4Ω 2Ω 3A 6Ω
22. Resistors in Parallel When resistors are in parallel this means that there is more than one path that the current can travel through. -Along each path that the current takes the voltage doesn’t change. -The current divides between each path. -The equation to find the total resistance of a parallel circuit is: 1/RT=1/R1+1/R I1 Plug in the numbers 1/RT=(1/1Ω)+(1/2Ω) Then Find the Common Denominator 1/RT=(2/2Ω)+(1/2Ω) 1/RT=3/2Ω Then take the reciprocal of both sides. RT=2Ω/3=0.667Ω I I1 V + + + Energy Energy Energy 2Ω 1Ω + + + + + + Energy Energy Energy Energy Energy Energy
23. Post CST Classwork 4 Find the total resistance of a circuit in parallel made up of two 10 Ω resistors. Draw the circuit from problem 1if the circuit is 10V. Find the total resistance of circuit A. What is the total current of circuit A. Find the total resistance of circuit B. Find the total current of circuit B. ** Find the currents I1,I2,I3. A I 4Ω 2Ω 10V B I1 I I3 I2 4Ω 2Ω 4Ω 24V
24. Series Circuit Lab First create a simple circuit. When you think you have it created, raise your hand and I will provide a battery to test your circuit. ____ 10 pts. Next create a 2 light bulb series circuit. When you think you have it created, raise your hand and I will provide a battery to test your circuit. __ 10 pts. Finally create a 3 light bulb series circuit. When you think you have itcreated, raise your hand and I will provide a battery to test your circuit. __ 10 pts.
25. Complex Circuits Complex Circuits are circuits with resistors that are both in series an parallel 4Ω A I 4Ω 4Ω 10V Find the total resistance of A. Find the total current of A Find the total resistance of B Find the total current of B Find the total resistance of C Find the total current of C. I 2Ω B 2Ω 2Ω 10V I1 I I3 I2 C 4Ω 2Ω 4Ω C 24V 8Ω
26. Symbols Quiz What does this symbol stand for? Current is measured using which units? The symbol for Resistance is? represents what? Draw the diagram for a resistor. The letter A stands for which concept. Ohms is represented by which symbol? Volts are the units that represent which concept. R has the units of ____ ? What diagram do we use to represent current? What are the units for the symbol I?
27. Parallel Circuits Lab First create a simple circuit. When you think you have it created, come to the front of the classroom to test it out. ____ 5 pts. Next create a 2 light bulb parallel circuit. When you think you have it created, come to the front of the classroom to test it out. __ 5 pts. Create a 4 light bulb parallel circuit. When you think you have it created, come to the front of the classroom to test it out. __ 5 pts. Create a 5 light bulb parallel circuit. When you think you have it created, come to the front of the classroom to test it out. __ 5 pts. Create a Series Circuit with all 5 bulbs. When you think you have it created, come to the front of the classroom to test it out. __ 5 pts. Use the circuit board to create a complex circuit _ 5 extra credit points.