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Download Investigating Electrical Circuits with the PhET Animation
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Version Purple Investigating Electrical Circuits with the PhET Animation: Circuit Construction Kit-DC only General instructions: You will use one or two online animations, your textbook, section assessments, and your guided notes to help you complete the following investigations. Circuit Construction Kit-DC only This animation allows you to drag objects onto the working area and move them around. Place objects close to each other to connect them. Control-click on a connection to see the options for that connection, including disconnecting the objects. Clicking on an object and using the delete key on your keyboard removes an item. On the right side of the application, you will see some options. Click “show values” in the options area. Use this animation for items 1-9. Key to this Document Instructions are in black. Experimental questions that you need to solve through experimentation with an online animation are in green highlighted. Data tables that you will fill out while experimenting are in aqua highlighting. Items that need a response from you are in yellow highlighted. Please put your answers to this activity in RED. Circuit Basics 1. Using the simulation “Circuit Construction Kit-DC only”, build a circuit that lights a light bulb, but only contains 3 components. (Also: Look in chapter 2.4 for help.) Insert a picture of that circuit below. (use Command-Shift-4 to take a picture of the circuit, and then drag it from your desktop to this document.) What 3 components does every electrical circuit need to be complete? 1A. 1B. 1C. 2. It is called a short circuit when you connect the electrodes of a cell (battery) with just a conductor and no load on the circuit. Do this on the animation. (Use chapter 2.6 for help on short circuits) Version Purple 2A. What happens? 2B. Why does this happen? 2C. Why would we want to avoid this? 3. Please make a complete circuit that includes a switch and lights one light bulb when the switch is closed. Insert a picture of that circuit below. (use CommandShift-4 to take a picture of the circuit, and then drag it from your desktop to this document.) Conductors vs. Insulators Keep the circuit you just created in #4, and separate the wires so you can place an object in the gap. Click on the grab bag and select each of the items so they are all on your workspace. 4. Put each of the items into the gap to discover whether it is a conductor or an insulator. List conductor or insulator for each item in the chart below. Item Dollar bill Paper clip Penny Eraser Pencil Lead Hand Dog 5. What do the conductors have in common? Conductor or Insulator? Version Purple 6. Why is the pencil lead a bit different than the others? Current In this section, you will build the circuits under each question and use your observations of the circuits to come to a conclusion/answer for each question. The circuits you build do not need to look the same as the diagrams in shape; they do need to be the same elements as shown by the symbols. 7. How is the amount of current affected by the voltage in a circuit? You will need to change the amount of voltage in the battery, and then for each voltage use the non-contact ammeter to measure the current. Notice also how the brightness of the bulb changes with the amount of current. Data Table Voltage Current Conclusion: 8. How is the amount of current affected by the amount of resistance in a circuit? You will need to change the amount of resistance provided by the bulb, and then for each resistance use the non-contact ammeter to measure the current. Notice also how the brightness of the bulb changes with the amount of current. Data Table Version Purple Resistance Current Conclusion: Series vs. Parallel Circuits 9. How does the current of a parallel circuit compare to the current in a series circuit with the same amount of bulbs ? Measure the current of each circuit with the non-contact ammeter found on the left. Please set the voltage of your battery to 25 Volts by control-clicking on the battery and choosing “change voltage”. Data Table Number of bulbs Current in series circuit Current in parallel circuit 2 3 4 Use the experiments you just did to answer the following questions: 9A. How does the number of bulbs in series affect the current in a circuit? 9B. How does the number of bulbs in parallel affect the current in a circuit? 9C. How does the number of bulbs in series affect the resistance in a circuit? 9D. How does the number of bulbs in parallel affect the resistance in a circuit? 9E. What happens in a series circuit when you remove 1 bulb? Version Purple 9F. What happens in a parallel circuit when you remove 1 bulb? Resistance 10. Now you will be using air through a straw to simulate electrons through a wire. Blow through the drinking straw. Next, cut the drinking straw in half and blow through a half-straw. 11. Was it more resistance or less resistance to blow through the shorter straw? 12. Cut the halves again in half, now you should have 4 quarters of a straw. With the four pieces, blow through one, then blow through all four made into a larger, square-shaped straw. 13. Was it more resistance or less resistance to blow through the thicker straw? 15. Next use the PhET simulation called “Resistance in a Wire” to complete the following statements: As wire length (cm) increases, the resistance (Ω) _________ As wire area (cm2) increases and the wire gets thicker, the resistance (Ω)_____ As wire density (Ωcm) increases, the resistance (Ω) __________ ______________________________________________________________ Review Statements: use these to see if you have learned the main points of this activity. Underline the correct choice: 1. For a circuit to be complete there must be a(n) broken / unbroken path for electron to flow through. 2. Conductors allow / prevent charges from flowing. 3. Short circuits are dangerous because a. they can cause lots of heat due to electrical friction b. they can catch on fire, or give people electrical shocks c. they can cause an energy source like a battery to be depleted (or “run out of electrical energy”) very quickly d. all of the above. Fill in the blank: 3. As the voltage in a circuit increases, the ____________________ also increases. Version Purple 4. As the resistance in a circuit increases, the current in the circuit __________________. 5. Wires that are thicker have ___________ resistance than thinner wires. 6. Longer wires have _____________ resistance than shorter wires. 7. When a wire has a ___________ temperature, its resistance becomes less. 8. Series circuits have __________ resistance than parallel circuits. 9. Series circuits have _________ path(s) for electrons to flow on, while parallel circuits have ____________ path(s) for electron flow.