Ch20_ListroR

**
 * Electrical Circuitstoc

= Investigation Part 1: =

1. What is needed to make a bulb light? Hypothesis: For a bulb to light, a power source and connection to the source via wires will be needed. Procedure/ Set-up: Test multiple circuits with the materials shown below (2 wires, battery, bulb). The below image displays the circuit that allowed the bulb to light. Data:     The data above shows various ways the wires were connected. The positives and negatives represent which end of the battery the wires were connected to. The other ends of the wires were fixed to their own individual metal clips in the socket. Conclusion: In order for a bulb to light, many more things are needed that what was stated in my hypothesis. Along with a power source and connection, there also needs to be one wire connected to the positive end of the battery and one connected to the negative end. The other ends of the wires must also be touching their own individual metal clip. There also must be a closed loop, meaning that a disconnection will result in a light going out. 2. What will happen to Bulbs 1 and 2 when you disconnect the wires of the configuration below at the various labeled points? Hypothesis: Both lights will go out at every connection because in order for a bulb to light, there needs to be a closed loop. Procedure/ Set-up: After connecting the complete circuit (as seen below), disconnect the circuit at the six different labeled points. Data: Conclusion: At every point of disconnection, the light in the bulbs goes out. In conclusion, the circuit needs to be connected in order to allow the flow of electrons from negative to positive. If there is not a full circuit, there will be no flow, and thus no light. In essence, there needs to be a closed loop in order for a bulb to light. 3. What type of object, when inserted into the space labeled "something" in the loop shown below, will allow the bulbs to light? Hypothesis: A conductor will be needed to be placed in the space labeled "something." Procedure/ Set-up: Connect the circuit as seen below. Leave the wires leading to "something" open, and test out various objects to see which ones complete the circuit and allow the bulb to light. Data: Conclusion: One will need a conductor to be the "something" in order to obtain light. If there is an insulator in the "something" place, there will be no flow of electrons from (-) to (+). A. Define and explain: What is a conductor and what is an insulator? How do you know? How can you test this using our loop configuration? A conductor allows for the flow of electrons, while an insulator does not. I know this because of the last investigation. I made an open circuit, leaving a space open between two wires, one connected to the socket and the other connected to the positive end of the battery. On the negative end, one end of the wire was connected to the battery and the other to the socket. I then connected the two open end of the wires with various objects. Some things were metal while others were not. In the end, the metal objects such as a paper clip and piece of tin foil lighted the bulb. 4. What parts of a socket and bulb are conductors and which are insulators? What is the conducting path through the bulb? Hypothesis: I think the metal parts of the socket will be conductors while the plastic bottom will be an insulator. The conducting path will run through the fixed metal strips on the blue plastic disc in order for the power to reach the light bulb. Procedure/ Set-up: After setting up a complete circuit, disconnect one wire from the bulb socket. Then touch the open wire end to the parts of the socket and see which ones allow the bulb to light. Then test out the parts of the bulb. Data: Conclusion: For the most part, my hypothesis was correct. In the socket, the clips and plates were conductors and thus allowed light. And in the bulb, the threaded section, filament, and tip were conductors and allowed light. The conducting path is represented by the following image: **PRACTICE SET: CCP** 5. How can you light a bulb using one battery, one bulb, and one wire ONLY? How many different correct ways can you do this? What DIDN"T work, why?  Hypothesis: The bulb will light by touching it to one side of the battery and connecting the wire to the other side of the battery and the bulb.   Procedure/ Set-up: Using the materials shown (one battery, one bulb, and one wire) create a circuit.    Data:      Conclusion: Using only a light bulb, battery, and one wire, you can light the bulb in 4 different ways. First, you can either touch the threaded section or tip of the bulb to the positive end of the battery. Then touch one end of the wire to the negative end of the battery and the other end to the part of the bulb that is not touching anything. For example, if the tip is touching the positive end, touch the free end of the wire to the threaded section and vice versa. The other two ways will occur when the bulb is on the negative end of the battery. The same scenarios presented on the positive end will also work on the negative end. Anytime the bulb was not touching the positive or negative end (for example just touching the part of the battery labeled energizer) did not work because there was no power source. Also, whenever the bulb was touching the battery via an insulator part, the bulb did not light because there was no flow of electrons due to the insulator. The last scenario that did not work was whenever the wire touched an insulator part of the bulb. It did not work because there was no electron flow. **PRACTICE SET: Basic Circuits** B. Define: What is a circuit? A circuit is a closed loop of conducting materials. 6. What does a compass tell you about what is happening in the wires of the circuit? Hypothesis: The compass needle will move when the wire is placed directly on top of it. Procedure/ Set-up: Set up a complete circuit, and place a compass under different points in the circuit. Make sure the compass and wire are facing the same direction every time. Data: When wire is placed in same direction of needle ...the needle attempts to move perpendicular to the wire. When wire is placed perpendicular to compass needle....nothing happens. Conclusion: The needle moves and attempts to move perpendicularly with the electricity flow. The needle will be deflected more with a stronger electricity flow. It deflects in the same direction when touched with the same end of a wire. When the wire is placed perpendicularly, the needle does not move because it does not have to since it has already achieved its goal of being perpendicular to the wire. 7. What effect does reversing the battery pack have on the compass deflection? What does this mean about the role of the battery in the circuit? Hypothesis: The needle will move in the opposite direction as in the previous investigation. Procedure/ Set-up: Use the same set up as the previous investigation. While keeping the compass under the wire, switch the two wires connected to the battery and observe what happens. Data: Confirms hypothesis. Conclusion: Whichever side (+ or -) the wire is plugged in to defines the path of the electrical flow. **PRACTICE SET: Wires** 8. What is a Genecon and how does it work? What does it tell you about the role of the battery in the circuit and why? Hypothesis: A Genecon will serve as a power source replacement for a battery. Procedure/ Set-up: Set up a complete circuit. However, remove the battery and plug in the Genecon (shown below) in its place. Data: When cranked at a constant speed and connected to a bulb, the bulb lights. When plugged into a battery, the crank begins to turn via the power from the battery. The circuit is completed when the power runs through the motor of the Genecon. Conclusion: A Genecon is a hand-powered generator. It is a low voltage powers source that lets you create electrical current by turning a crank. When you turn the crank with your hand, energy is transferred to the gears which move the motor. The power transferred into the motor then transfers electricity to the wires. W(from crank)=Ue (into wires)  This investigation shows that the battery is able to be replaced by another power source, such as a Genecon. ** READINGS: Schematic Diagrams ** C. DEFINE and EXPLAIN: What is a schematic diagram? What are the symbols for the various circuit elements? Schematic diagrams represent the components of a circuit through symbols. Some symbols include:  (symbols on the right column) **PRACTICE SET: Schematics** **READING: Capacitance** D. DEFINE and EXPLAIN: What is a capacitor and how is it made? A capacitor is a device used to store electricl energy through a connection to a power source. It is made out of three layers– two layers of conductors separated by a layer of insulating material. These layers are wrapped into a cylinder, then a terminal is connected to each conducting layer. When plugged into a closed circuit, charge moves from the positive end of the power source and builds up in one terminal. When this happens, the built-up positive charge emits a positive electric field and repels the like-charge in the other terminal. When still connected to the battery, the bulbs light for a small amount of time, which depends on the amount of power and the capacitor's capacity. When one wire is disconnected and then touched to the other wire, the bulbs light temporarily. This happens because there is a conducting loop consisting of the repelled charges moving away from the charges of the opposite terminal. 9. What is the effect of a capacitor on a closed loop? Hypothesis: Circuit A will not light unless there is charge already stored in the capacitor. Circuit B will light once the wire are reset, which occurs when they touch each other after being connected to the circuit. Procedure/ Set-up: Set up the following circuits. Data: Confirms hypotheses. Conclusion: A capacitor is a device used to store energy though a connection to a power source. They eventually stop flow of charge. 10. What is origin of mobile charge? From where does the mobile charge originate during the charging and discharging process? Hypothesis: In the charging circuit, the mobile charge will originate from the batteries. In the discharging circuit, the mobile charge will originate from the built-up charge stored in the capacitor. Procedure/ Set-up: Set up the following circuits. The charging circuit should have three batteries, two bulbs, and a capacitor connected to it. Data: Confirms hypothesis. Conclusion: Mobile charge is from where the circuit gains positive charge that flows in the circuit. During the charging process, mobile charge originates from the conductors in the circuit. The charges are pushed by the battery to the first conducting terminal. During the discharging process, mobile charge comes from the built-up positive charge in one conducting terminal. The charge then repels the positive charge in the other terminal and pushes it through the circuit. **PRACTICE SET: Electrical Energy** **INVESTIGATING: Air Capacitor** **PRACTICE SET: Capacitance** Reading: Current Electricity > I understand that, to be a true circuit, charges must continually flow through a complete loop, returning to their original position and cycling through again. There must be a continual loop of conducting materials in order to allow the flow of electrons, which will carry the charge needed to power a certain object such as a light bulb. > I also understand the use of a compass in a circuit. When all the wires are connected to the battery and light bulb, the light bulb lights and the compass needle deflects. The needle serves as a detector of moving charges within the wire. When it deflects, charges are moving through the wire. And if the wire is disconnected at the battery pack, the light bulb is no longer lit and the compass needle returns to its original orientation. When the light bulb lights, charge is moving through the electrochemical cells of the battery, the wires, and the light bulb filaments; the compass needle detects the movement of this charge. It can be said that there is a current - a flow of charge within the circuit. > At first, I did not understand the use of the electric field in its context. However, it started to make sense when I realized that there would be a natural motion from positive to negative, but an unnatural movement when the cycle needed to continue after that. This is where the battery comes to good use; using its power, it needs to pump the charge back from the negative side to positive side to continue the loop of electric circuit. > What are drift speeds and what are the point of them? > I thought it was interesting to read about how batteries worked. Throughout my entire life, I have wondered the same thing when I needed to put new batteries in my television remote or my XBOX 360 controller. However, I never realized how they actually worked. Now I know that, when I am holding that remote or controller, the fresh batteries I just put in there are passing electrons through the device in my hands.
 * ~ Disconnected At... ||~ Result ||
 * A || Lights out ||
 * B || Lights out ||
 * C || Lights out ||
 * D || Lights out ||
 * E || Lights out ||
 * F || Lights out ||
 * ~ "Something" ||~ Result ||
 * Paper clip || Light ||
 * Tin foil || Light ||
 * Cardboard || No light ||
 * ~ Location ||~ Reaction ||
 * Socket ||  ||
 * * Clips || Light ||
 * * Plates || Light ||
 * * Base || No light ||
 * Bulb ||  ||
 * * Filament || Light ||
 * * Glass || No light ||
 * * Threaded section || Light ||
 * * Tip || Light ||
 * * Black ring || No light ||
 * 1) What (specifically) did you read that you understand well? Describe at least 2 items fully.
 * 1) What (specifically) did you read that made you feel little confused/unclear/shaky, but further reading helped to clarify? Describe the misconception(s) you were having as well as your new understanding.
 * 1) What (specifically) did you read that you don’t understand? Please word these in the form of questions.
 * 1) What (specifically) did you read that you thought was pretty interesting, that you didn't know before, or can easily apply to your every day life?

= Investigation Part 2: =

1. What effect does the type of bulb have on a capacitor during charging and discharging? Hypothesis: Because of the different properties of different bulbs, the discharging will last longer amounts of time and produce different brightnesses.

Set-up/ Procedure: After creating a standard circuit, a capacitor was added between the two bulb sockets. Whenever during the charging process, round bulbs were used to ensure that the same amount of charge was available for each circuit. After charging, discharge different times with round bulbs, long bulbs, and the Genecon. Data: Long bulbs had a brighter and longer flash of light (approximately 4 seconds). Round bulbs lasted about 1 second and were very dim. The Genecon lasted about .5 seconds, which translated into about one full turn of the handle. It was also able to charge the capacitor.

Conclusion: There is less resistance through round bulbs than long bulbs and the least resistance through the Genecon. The resistance will affect the brightness and length of the light during the charging and discharging processes. More resistance will result in a longer and brighter light of the bulb because a higher resistance will make the charge slow down and take more time passing through the bulb, thus elongating the lighting process. Because the circuit is always charged with round bulbs, the discharging process will always have the same amount of charge running through the circuit. With different bulbs, there are different resistances, thus resulting in different results for the discharging process with each different output (bulb or Genecon).

2. What are the differences between the filaments of round and long bulbs? (Use a microscope.) Hypothesis: Due to the previous investigation, the long bulbs will have longer and thinner filaments when compared to the round bulb filaments.

Set-up/ Procedure: Place a round bulb and long bulb under a microscope and observe the filaments of each. This can be found be looking in the area between the two pieces of metal that seem to fork away from each other. Data: Long bulbs had longer and thinner filaments. Round bulbs had shorter and thicker filaments that seemed to be structured in a thick coil

Conclusion: The long bulb had a longer and thinner filament while round bulbs have a thicker and shorter one. Therefore, long bulbs will have more resistance to an electrical current.

3. How is air moving through straws analogous to charge moving through a filament? When one tries to blow through a longer and thinner straw, one will find it more difficult to do so when compared to a thicker, shorter straw. This is similar to a filament because charge will move easier through a thicker, shorter filament. A longer and narrower filament will not allow charge to move with the same ease. Also, using multiple straw lined up next to each is easier than using just one alone. This is similar when comparing parallel and series circuit. In a parallel circuit, which is analogous to using multiple straws, there is more room for the charge or air to move through because there is "less traffic."

4. What is the difference between flow rate and flow speed? Flow rate is is the amount of charge that moves over a certain amount of time, while flow speed is the amount of distance a charge moves over a certain amount of time.

5. How does the number of bulbs in a single loop affect the overall current and resistance in a circuit? Hypothesis: More bulbs will result in more total resistance and a slower current. therefore, the bulb brightness will decrease with more total bulbs.

Set-up/ Procedure: Use the below diagrams to set up three different circuits. After completing each circuit, observe the brightness of the light bulb(s) and place a compass under the wire to determine the total amount of deflection, which will determine the strength of the overall current. Data:
 * ~ Circuit A: 1 Bulb ||~ Circuit B: 2 Bulbs ||~ Circuit C: 4 Bulbs ||
 * Very bright, may be bright enough to eventually blow out the bulb

Most deflection shown in the compass || Less bright than 1 bulb, brighter than 4 bulbs

Bulbs of equal brightness

Not as much compass deflection || Very dull light; dullest of the three total circuits

Compass deflects less than the other circuits || Conclusion: There will be more resistance with more light bulbs. As a result of the increased resistance, current will be slower, which will decrease the brightness of the lights bulbs and the amount of deflection in the compass.

6. Problem Set: RESISTANCE 7. Read and Summarize: @http://www.physicsclassroom.com/Class/circuits/ 8. Reading: PRESSURE DIFFERENCE 9. Activity: COLOR CODING 10. Practice Set: COLOR CODING 11. How does the number of bulbs side-by-side affect the overall current and resistance in a circuit? Hypothesis: Adding light bulbs will not affect the brightness because there is "less traffic" flowing through the bulbs. Equal charge will move through the parallel wires once the current passes past each junction.

Set-up/ Procedure: Set up the below connections. After each circuit is set up, observe the brightness of the bulbs and the compass deflection. Data:
 * ~ Circuit A ||~ Circuit B ||~ Circuit C ||
 * 1 bulb

Bright

Little resistance || Less charge through each wire

2 bulbs

Bright

Little resistance through each bulb || 3 bulbs

Bright

Little resistance through each bulb

Least charge through each bulb || Conclusion: The number of bulbs in a side-by-side setup will not affect the overall current because no matter what the setup, there will still be the same color code: red coming from the positive side of the bulb and blue on the negative side of the bulb. Although the resistance increases due to the increase in bulbs, the parallel setup allows the charge to be spread out and move with less traffic, which is caused by the amount of options presented at the trunk.

12. Does adding wires in series or in parallel affect the overall resistance of the circuit?

Hypothesis: Adding wire will not affect the resistance to the circuit because the wires used have negligible resistance.

Set-up/ Procedure: Set up the circuits below. Circuit A is a traditional circuit, circuit B has additional wires connected between the two bulbs, and circuit C has a an additional wire whose ends are connected to the two plates in the bulb socket. Data: Circuit A and B have the same brightness. In circuit C, the additional connection results in the bulb in the connected socket to go out.

Conclusion: Adding a wire in a series between bulbs does not affect the overall resistance because the wires used presented a negligible resistant. On the other hand, when a wire is placed in parallel with another bulb, the light in the bulb goes out. This happens because, when charge moves to the trunk, it has an option to go through the bulb or the wire. Because charge always moves to the option with a lesser resistance, charge only moves through the wire, which has little to no resistance. This results in no charge moving through the bulb, and thus no light in the bulb. Overall, the total resistance would lessen because the circuit would act as if there is only one bulb and two wires.

13. What effect do dueling battery packs have on bulb lighting and flow rate?

Hypothesis: In a series, dueling battery packs offer resistance when facing in the opposite direction, and their voltage together when facing the same direction. In a parallel set-up, the effect is basically negligible.

Set-up/ Procedure: Set up the below circuits and observe the brightness of the bulbs. Data:
 * ~ Circuit A ||~ Circuit B ||~ Circuit C ||~ Circuit D ||~ Circuit E ||~ Circuit F ||~ Circuit G ||
 * No dueling

Same as using 3 batteries || Bulbs have same brightness as that of bulbs with 2 batteries || Same brightness as 1 battery

Negligible brightness || Same brightness as 0 batteries

No light || Same brightness as 3 batteries || Same brightness as 0 batteries || Same brightness as 3 batteries ||

Conclusion: When additional battery packs are placed in series with each other, the effect will be a result of "adding" or "subtracting" the power of the batteries from each other. When the battery packs are placed in the same direction, their voltages will add together. For example, if two 3-battery packs are placed in this situation, the bulbs in circuit will have the same brightness as they would when connected to six batteries. On the other hand, when the battery packs are facing opposite directions, their voltages will subtract. For example, if there are two 3-battery packs facing opposite directions, the bulbs in the circuit will not light because the result will be the same as connecting bulbs up to zero batteries. This happens because, when battery packs are facing opposite directions, their voltages are moving towards each other and the result will be the difference between the voltages. When a battery pack is added in parallel to another battery pack, the result is negligible. There is no change in brightness of the bulbs because there is still the same color coding and flow rate as there was without the parallel battery pack.

14. Practice Set: BATTERY STRUCTURE 15. How does mixing bulbs in series affect flow rate and pressure in each part of the circuit?

Hypothesis: Mixing bulbs will cause the circuit to flow at the rate of the most resistant bulb. This will cause the less resistant bulb to have a higher brightness than the more resistant one.

Set-up/ Procedure: First set up the following circuit without the capacitor. Observe the brightness of the bulbs. Complete the connection to the capacitor and observe what follows afterwards.

Data/ Conclusion: Mixing bulbs does affect the flow rate and pressure in each part of the circuit. Current is flowing at the same rate throughout the entire circuit. It will be moving at the speed of the slowest bulb, which will be the result of whichever bulb that has the greatest resistance. The amount of charge that the more resistant bulb allows through will not be enough to light the less resistant bulb. In this case, long bulbs have more resistance than round bulbs. This is why there was only light present in the long bulbs. In the circuit with the capacitor, the capacitor ends up short circuiting the long bulb during the charging process. This occurs because the capacitor initially has less resistance than the parallel bulb. Because current moves from high to low pressure, the charge moves into the capacitor instead of the bulb. During that time, the round bulb lights due to the increase in flow rate. As the capacitor becomes charged, the resistance increases, causing the current to flow through the long bulb again. The circuit continues to flow as it did prior to the charging process.

16. Reading: MIXING BULBS 17. What is the effect of adding another round bulb in parallel?

Hypothesis: Adding an additional bulb in parallel to the already existing bulb in the middle will increase the flow rate and cause all of the bulbs to get brighter.

Set-up/ Procedure: Set up the 3-bulb circuit in figure on the left, with a gap for a 4th bulb to be added. Then add the 4th bulb to form the circuit in figure on the right. To switch back and forth between the two circuits, you can add the 4th bulb and its socket, and simply unscrew the 4th bulb to break the connection. Data: When the additional bulb is added, the bulbs in a series (1 and 4) get brighter, while the parallel bulbs (2 and 3) do not show any change in brightness.

Conclusion: When adding another round bulb in parallel, the flow rate increases because the parallel bulbs provide two options for charge to flow through, which decrease the "traffic" of the circuit. This results in the two outer bulbs getting brighter and the two parallel bulbs getting dimmer. The two bulbs in series get brighter because the flow rate increases. On the other hand, however, the two parallel bulbs do not get brighter because they are sharing the current that approaches and flows through the trunk at which the bulbs are connected to.

18. How does the addition of another branch affect flow rate and pressure in the wires? Assemble a circuit with a 3-cell battery and a round and long bulb in series. Using a compass, measure the flow rate in wires A and B. Add a branch with a second long bulb parallel to the long bulb, but don't make the connection. Predict what will happen to the bulb brightness and flow rate when the connection is made. Repeat for a round bulb and for a connecting wire.

Hypothesis: By adding an additional bulb in parallel, the flow rate will increase, causing the compass to deflect more. Out of the three circuits, the compass will deflect the most in circuit three because, due to the parallel wire shorting the long bulb, the circuit will only have resistance in the round bulb.

Set-up/ Procedure: In the three below circuits, place a compass on the three different locations indicated by the letters. Observe the deflection of the compass to compare the flow rate at the different locations throughout each circuit. Data: When adding a bulb with lower resistance, the compass deflected more. The most compass deflection occurred when a lone wire was added. The second most deflection occurred when the round bulb was added. The least deflection occurred when the long bulb was added. With less resistance, the bulbs became brighter.

Conclusion: By adding another branch, the flow rate increases, which is shown in the amount of compass deflection in the three different circuits. For circuit one and two, the pressure was the same. However, for circuit three, the pressure increased due to the parallel wire shorting the long bulb. the flow rate increases because the additional branch provides another option that the charge can flow through. In turn, this creates "less traffic" which leads to an increase in flow rate.

19. What is the effect of decreasing the resistance of right side of the circuit on: a) the flow rate through the battery; b) the pressure difference across the battery; c) brightness of the left bulb

Hypothesis: By adding one and eventually two round bulbs to the right of the circuit, the flow rate will increase, however, the pressure difference will not be affected, and therefore, the long bulb on the left will keep a consistent brightness.

Set-up/ Procedure: Set up the following circuits and observe the brightness of each bulb as new elements are added to the circuit. Data: There is no change in brightness. || Compass deflects more, indicating the flow rate increases. The brightness of long bulb is unchanged. || Compass deflects more, indicating the flow rate increases. The brightness of the long bulb does not change. ||
 * ~ Circuit A ||~ Circuit B ||~ Circuit C ||
 * Compass deflects more, indicating the flow rate increases.

Conclusion: Decreasing the resistance of the right side of the circuit increase flow rate through the battery, and keep the pressure difference and brightness of the left bulb constant. the flow rate increases because less resistance is added to the right side. This is proven through the amount of compass deflection, which increased with less resistance. The pressure difference remains constant because the color coding is still the same. Lastly, the brightness of the left long bulb stays the same because it is not affected by the branch in parallel to the battery.

20. Practice Set: PRESSURE IN THE WIRES 21. Activity: Ammeter Voltmeter. Hypothesis/ Data: A. (Each Setup and Procedure are On the Sheet)

B. Greatest- E, A, C, D, F, B, G, H - Least

Analysis: Discussion Questions: Conclusion: There will be a different affect on the quantitative current and volt readings when dealing with parallel and series circuits. In series, the currents will all equal each, while the voltages will, when added together, will equal the total voltage of the power source. On the other hand, in parallel, the voltages of each parallel branch will equal each other while the currents, when added together, will equal the total current of the power source.

22. True/ False Worksheet

= Part 3: Quantitative Analysis = 1. Guiding Questions #1-6 2. Read and Summarize Lesson 2 with Method 4 3. Guiding Questions #7-14 4. Read and Summarize Lesson 3 with Method 4 5. Chapter 20 Problems- in Homework Notebook

6. Ohm's Law Experiment
Purpose: To find the relationship between pressure difference and current. To find the difference between Ohmic and non-Ohmic materials.

Hypothesis and Rationale: When resistance is left at a constant value and potential difference is increased, the change that current experiences will be directly proportional to that of the potential difference. This will happen because, as seen in previous investigations in Part 1, when more batteries are added to a circuit, bulbs get brighter and thus the flow rate (or current) increases as well.

Materials: variable power supply, batteries/ holders, long bulb and socket, assorted resistors, multimeters, lead wires

Set-up/ Procedure: 1. Set up the above circuit. As the power supply, use a variable power supply, one that can change voltage. 2. Use four different resistors during the experiment– a long and round bulb, and two different resistors. 3. After completing the circuit with each of the four resistors, vary the voltage of the power supply and see what appears on the ammeter. This will indicate the current of the circuit. 4. Record both the voltage (potential difference) and current in excel for each different voltage and resistor. In order to display the relationship between the two, graph potential difference versus current.

Data: Sample Calculations: Graphs: Note: Resistor 1 is the line labeled 68 Ohms, Resistor 2 is 22 Ohms, long bulb is 60 Ohms, and round bulb is 10 Ohms.

Analysis: The shapes for the four lines in the above graph have either a linear or power fit. Both resistors that we used had lines with linear fits, indicating that they are Ohmic resistors, which means that they follow Ohm's law. On the other hand, the two bulbs had lines with a power/ polynomial fit, indicating that they were non-Ohmic resistors, which means that they do not follow Ohm's law. The slope for both of the resistors is equal to electric potential divided by current. According to Ohm's law, this equals resistance, so, in the end, the slopes of the resistors should equal their experimental resistance. They y-intercept for all four of the lines is zero because, when there is zero voltage, there is also no zero current. That leaves the equation of the line to be V=IR, leaving V as the y, I as the x, and R as the slope. All four of these lines also had strong R^2 values close to 1, meaning that the lines of best fit are good for judging future predicted y-values.

Discussion Questions: Conclusion: My hypothesis was correct; as voltage increased, so did current. This occurred due to the fact that resistance was kept constant. In order to keep it constant while voltage increased, current had to also increase proportionally to the voltage. This is shown in the above data table. For each individual resistor, one could see that as voltage increased, so did current. For some resistors in this lab, there was not much error. However, on the other hand, other resistors experienced a lot of error. One particular resistor that experienced a lot of error was the long bulb, which had up to 50%. One source that can attribute to a lot of this error is the predicted resistance. As we performed this experiment, we did have a certain value for the long bulb's resistance. We knew that the long bulb had a resistance of around 60 ohms, however, we did not know the exact value. Also, because the bulbs we used were not new, there could be a source of error that shows that the bulbs had a resistance much less than 60. This is a much different situation than the Ohmic resistors, which had a resistance provided by the manufacturer right on it. The error experienced by these resistors can be attributed to the last ring on the resistors. This ring, which was 5% on both of the resistors we used, displays the amount of error in the resistance it may provide. This error can only be from one source– the manufacturer. In the future, I would definitely used brand new light bulbs to eliminate any speculation in the age of the bulbs. This experiment can have a real-life application when dealing with circuit boards and electronics. If I ever needed to prevent a certain circuit from receiving too much voltage, I would have the knowledge of knowing that a resistor can solve my problem and prevent my circuit from receiving too much current.

7. Optional Gizmo 8. Guiding Questions #15-17 9. Read and Summarize Lesson 4 with Method 4 10. Chapter 20 problems- in Homework Notebook 11. Optional Gizmo 12. Guiding Questions #20 13. Textbook Problems- Done in Homework Notebook 14. Optional Gizmo 15. Guiding Questions #30-38 16. Textbook Problems- Done in Homework Notebook

17. Kichoff's Rules Lab
**Purpose:** To determine how currents splits in multi-loop circuits.

**Hypothesis with Rationale:** As current reaches a split in a given wire, charge will have two different wires to flow through. This availability of options will split the current. Depending on the resistances of the two different options, more current will flow through the option with less resistance due to its trait of wanting to move to less resistant areas.

**Procedure:** 1. Set up each of the four circuits shown below. (Also see circuits shown in "Data:.") 2. Draw a schematic diagram for each, labeling each resistor and battery pack. 3. Using an ammeter and voltmeter, calculate the current and voltage of each power source and resistor. These values will be this lab's theoretical values. 4. In each circuit, label each current, following Kirchoff's Junction Rule and Loop Rule. After, calculate the current in each resistor and power source using matrices. These will be the experimental values. 5. To determine how "good" your calculated data is, compare it with the theoretical values by calculating the percent error.

**Materials:** Resistors, wire leads, D-cell batteries, several digital multimeters, (2) power supplies, 3-4 resistors, connecting wires

**Data:** Schematic Diagrams



Quantitative Data

**Sample Calculations:** Current Calculations Miscellaneous Calculations  I(mA)/1000=I (A)

**Analysis:**

**Discussion Questions:** **Conclusion:** For the most part, my hypothesis was correct. When the current reached a split in its wires, the current could move through two different options in wires. Generally, more current flowed through the wire with less resistance. For example, in circuit A, when current reaches the first junction when I1 splits into I2 and I3, there are two different wires current can flow through: one with a 100 Ohm resistor and another with a 560 Ohm resistor. As seen in both our theoretical and experimental data, there was a greater current that flowed through the 100 Ohm resistor when compared to that of the 560 Ohm resistor. There was some error experienced in this lab. Although there was a very small amount of error for most of the resistors (ranging from .13% to 15%), the most error was experienced in the power source's current and voltage. The battery in Circuit A experienced about 32% error, the batteries in Circuit B experienced about .16% and 3% error, the batteries in Circuit C experienced about 1% error each, and the batteries in Circuit D experienced about 8%, 2%, and 11% error. The reason for most of this error can be accounted for by resistance that was not taken into account. Both the ammeter and the wires used in this lab contain a very small amount of resistance; however, neither resistances were taken into account. Another resistance not taken into account was the internal resistance of the power sources. D-cell batteries were only used in circuits A and D. All of the batteries used in both of these circuits experienced a larger amount of error than the power sources used in circuit B and C. This shows that there may have been additional resistance on the inside of the batteries used. The last source of error is in the resistors. Because manufacturers cannot really develop resistors with an exact resistance, they provide a range of resistance that their resistors possess. Generally, the resistors used in these circuits were about +/- 5%. If I were to redo this lab in the future, I would want to take into account the internal resistance of the power sources. If I could not determine this resistance, I would just use variable power supplies, as they provide a steady voltage that does not have any internal resistance, unlike their D-cell battery counterpart. In real-life, I would be able to apply my knowledge from this lab when developing circuits. If I wanted a certain object to receive more current than another object, I would set these objects up in parallel and add a larger resistor to the branch with the object that needs less current.

18. Quiz 19. Guiding Questions #15-17