Lab building Electrical Circuits, assignment help

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This may seem like a lot of work but it really isn't the attachment (4.5B Circuits Directions i) is added to help you visualize on what to do for this lab which means you dont have to complete it.

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Physical Science Building Electrical Circuits Problem To construct series and parallel circuits and measure the voltage and current through each type of circuit Background Electronic devices like your computer or video game system require a certain amount of electrical current to operate. The amount of current necessary can be determined easily by the principles of electronics. If we obey these principles, the devices will work just fine; if not, they won’t function properly. Before building an electrical circuit for a device, you must first know all about the device you are trying to build. You need to know if you can use series or parallel connections to control the current for this device. As you will learn in this lab, there are benefits to both kinds of connections. In this lab, you will study each type and learn the different applications of series and parallel circuits. Activity B: Series Circuits Using the instructions provided in the Student Exploration Sheet, create a series circuit as shown. Continue following the directions and answering the questions until you get to the Activity C box. Observations In the first circuit you build, how does changing the voltage in a circuit affect the current in the circuit? ____________________________________________________________________________ ____________________________________________________________________________ What is the impact of adding more light bulbs in series? ____________________________________________________________________________ ____________________________________________________________________________ In the series circuit, is the current constant throughout the circuit, or does it vary? ____________________________________________________________________________ ____________________________________________________________________________ Activity C: Parallel Circuits Using the instructions provided in the Student Exploration Sheet, create a series circuit as shown. Continue following the directions and answering the questions until you get to the question 7. © 2014 Connections Education LLC. All rights reserved. Observations What is the impact of adding more light bulbs in parallel? ____________________________________________________________________________ ____________________________________________________________________________ In the parallel circuit, is the current constant throughout the circuit, or does it vary? ____________________________________________________________________________ ____________________________________________________________________________ Conclusion Answer all questions in complete sentences and use supporting details. 1. Analyze: In the series circuit what characteristic was common throughout the experiment? What changed as you added more light bulbs? 2. Analyze: In the parallel circuit what characteristic was the same throughout the experiment? 3. Conclude: Why would knowing the characteristics of circuits be important in designing electrical circuits? © 2014 Connections Education LLC. All rights reserved. Student Exploration: Circuits Vocabulary: ammeter, circuit, current, electron, ohmmeter, Ohm’s law, parallel circuit, resistance, resistor, series circuit, voltage Prior Knowledge Questions: (Do these BEFORE using the Gizmo.) Strings of holiday lights can be designed in one of two ways. In some strings of lights, each light is connected to the others along a single wire (in series). In others, each light is attached to its own wire (in parallel). 1. Suppose a single light bulb burns out. How do you think this will affect lights that are strung along a single wire? 2. How will a single burned-out bulb affect the string of lights if each light is attached to its own wire? Gizmo Warm-up The Circuits Gizmo™ shows a circuit board and a variety of components. Create a circuit with a battery, a light switch, a wire, and a light bulb, as shown in the picture to the right. (Click the light switch to turn it to OFF.) 1. Click the light switch to turn it to ON. What happens? 2. Turn on Show current and select Electron flow. The moving dots represent a current of electrons—tiny, negatively charged particles—moving through the wire. Voltage is a measure of how much more potential energy an electron at one end of a battery has than an electron at the other end of the battery. A. . How does changing the battery’s voltage affect the current? B. How does changing the battery’s voltage affect the brightness of the light? 3. Remove the wire. What happens? Activity B: Series circuits Get the Gizmo ready:  Click Clear.  Create a circuit as shown.  Click the battery to select it. Set the Selected battery voltage to 10 volts. Question to Keep in Mind: In a series circuit, there is only one path for charge to flow. What are the properties of series circuits? 1. Observe: Turn the light switch ON and observe the light bulb. Then start replacing the wire segments with new light bulbs. A. How does each new light bulb affect the others? B. Use the Ammeter to measure the current in various parts of the circuit. Is the current the same throughout, or does it change? 2. Form hypothesis: How do you think the total resistance of a series circuit is calculated? 3. Experiment: Create a series circuit with a 10-volt battery and four 10-ohm resistors, as shown. Measure the current. A. Based on the voltage and current, what is the resistance of the circuit? (Hint: Use Ohm’s law.) B. Ohmmeters measure resistance. Remove the battery and attach the terminals of the Ohmmeter ( ) to the ends of the circuit, where the battery used to be attached. What is the resistance? 4. Make a rule: How do you calculate the total resistance of a series circuit? Test your rule using the Gizmo. If necessary, modify your rule. 5. Extend your thinking: Replace the battery. Turn on Show current, and remove one resistor. Why would it be a problem if your household appliances were connected in a series circuit?  Now go to the worksheet you will turn in and answer the Activity B: Series Circuit questions on the first page. Activity C: Parallel circuits Get the Gizmo ready:  Click Clear.  Create a circuit as shown.  Click the battery to select it. Set the Selected battery voltage to 15 volts. Questions to Keep in Mind: In a parallel circuit, there is more than one path along which charges can flow. What are the properties of parallel circuits? 1. Observe: Turn the light switch ON and observe the light bulb. Then add two more light bulbs to the circuit, parallel to the first two. A. How does each new light bulb affect the others? B. Use the Ammeter to measure the current in various parts of the circuit. Is the current the same throughout, or does it change? Explain: 2. Form hypothesis: How do you think the total resistance of a parallel circuit is calculated? 3. Experiment: With the battery voltage set to 15 volts, measure the current in a parallel circuit with 1, 2, 3, and 4 light bulbs. (In each case, place the ammeter next to the battery.) Use Ohm’s law to calculate the total resistance of the circuit. Record results below. Number of light bulbs Voltage Current Total resistance 1 15 volts 2 15 volts 3 15 volts 4 15 volts 4. Make a rule: How would you find the resistance of a parallel circuit with n identical resistors? 5. Apply: What will be the total resistance and current in a parallel circuit with a 15-volt battery and three 10-ohm resistors? Test your answers with the Gizmo. Total resistance: Current: 6. Extend your thinking: Household appliances are usually connected in a parallel circuit. Why do you think it might be a problem if too many appliances are turned on at once? (Hint: current in a wire also produces heat.) 7. Calculate: Determining the total resistance of a parallel circuit when there is a variety of resistors is more complex.  The total current in the circuit (I) is equal to the sum of currents in each branch:  Ohm’s law (V = IR) can be rewritten as I = V / R. Substituting this expression into the equation above:  (Note: Since each branch of the circuit might have a different resistance, we write R1, R2, and so forth. But the voltage is the same across each branch, so V is used for each term.) Divide each side of the equation by V, and you get an expression for the total resistance of the circuit:  8. Practice: Determine the total resistance of each of the following parallel circuits. Then use the Gizmo to check your answer. (You can calculate the total resistance from the current and voltage using Ohm’s law, or use the Ohmmeter to measure the resistance directly.) A. A parallel circuit with a 20-ohm resistor and a 10-ohm resistor. B. A parallel circuit with two 20-ohm resistors and a 10-ohm resistor. C. A parallel circuit with a 15-ohm light bulb and a 20-ohm resistor. D. A parallel circuit with two 100-ohm resistors and a 20-ohm resistor. E. A parallel circuit with a 10-ohm, 20-ohm, 100-ohm and 200-ohm resistor.  Now go to the worksheet you will turn in and answer the Activity C: Parallel Circuit questions.  Then answer the Conclusion questions on the second page. In all questions, remember to write complete sentences and use the data collected to support your explanations. When you have answered all questions, turn in only the answer sheet to the unit 4 portfolio drop box. You will keep this worksheet saved on your computer. If you printed this worksheet and wrote your answers, then keep this worksheet in your science binder/folder.
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Activity B (Series Circuits) – Observations
If you increase the voltage in the circuit, the current will also increase. Likewise, if you decrease the
circuit voltage, the current also decreases.

While holding voltage constant, adding more light bulbs in series increases the resistance in the circuit,
which ultimately reduces the current in the circuit. All light bulbs will have the same brightness in a
series circuit.

In a series circuit, the current does not change. It remains constant at all points throughout the circuit.

Activity C (Parallel Circuits) – Observations
Adding additional bulbs in parallel changes increases the amount of current in the circuit.

In a parallel circuit, the current is not constant. The current varies when measured along different wires.

Conclusion
1. The circuit voltage remained constant in the experiment. As you added more light bulbs, you
changed the overall resistance in the circuit, which ultimately caused the current to decrease.
With a series circuit, if one bulb were to burn out, or be removed, the flow of electricity would
stop and all lights would go out.

2. The circuit voltage remained constant in the parallel circuit. The current varied across different
branches within the circuit, and changed as new bulbs were added in parallel. As more bulbs
were added, the current increased. With a parallel circuit, if one bulb were to burn out, or be
removed, the flow of electricity would continue along the other branches, so the remaining
lights would stay lit.

3. ...


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