1. U9A2 Intro to Current Electricity (Part Deux)

2. Part 1: Role of Battery in Circuit (Take 2) We need a model for the battery: Using the virtual circuit, we have seen that the “Battery as the Source of Charge” is fundamentally incorrect. The battery is not the source of charge. Charge (i.e., mobile electrons) are present in all parts of the conducting path – even in useless circuits with no battery! So, then, what is the model that best suits the battery’s true role in making electricity happen? Watch the video clip on the next page for a suggested model (you will need to have the sound on).

3. Part 1: Role of Battery in Circuit (Take 2)

4. Question 1 : In the video clip, we see that the water pump is not the source of water in the “water circuit.” However, the water pump does add something to the circuit. What is it? [Hint: Think about what the water has in the top reservoir that it doesn’t have in the bottom reservoir.] Question 2: In the video clip, what is the suggest role of the battery in a circuit? Question 3: We see that the battery is not the source of charge. However, does the battery “put” anything into the circuit? What is it?

5. Part 2: Mobile Electron Flow Rate “The Standard Circuit”: In the virtual lab, we will be working with the “1 battery, 1 bulb and a switch” circuit a lot, so we’re giving it a name: “The standard circuit.” Make this make whenever you are instructed to build the standard circuit. Measure Mobile Electron Flow Rate: 1.Build the standard circuit. Close the switch and observe the mobile electrons. 2.Use a timer to determine the flow rate of mobile electrons through the battery. Feel free to partner with someone to make this less stressful.timer 3.Assume each blue sphere represents the quantity of electrons equivalent to 1 coulomb of charge. Record in the space to the right the flow rate of electrons in coulombs per second Flow Rate of Charge

6. Part 3: Does Electron Flow Rate Matter? OK, so we can quantify flow rate of charge in a circuit, but does it matter? Can the flow rate of it charge change in a circuit? Let’s find out! Question 3: Right click on the battery in your standard circuit. You will see that you can change the voltage of the battery. For now, in our “battery as charge pump” analogy, you can think of the voltage of a battery as an indication it’s strength pump strength or size. Low voltage = little, weak pump; High voltage = big, strong pump. What happens to the flow rate of charge when you increase the voltage? Doe the flow rate of charge affect bulb brightness? How?

7. Part 3: Does Electron Flow Rate Matter? Question 4: We see that charge flow rate affects bulb brightness. Why do you think this is the case? Question 5: Lower the voltage the battery until the bulb is no longer lit. You should see that charge is still moving through the filament. Why do think the bulb is not emitting visible light if charge is moving through it.

8. Part 4: Drawing Circuit Diagrams Drawing Circuit Diagrams http://www.digikey.com/schemeit/

9. Part 4: Scheme-It Online Tool

10. Part 4: Drawing Circuit Diagrams Make a schematic of this circuit Paste a copy of your schematic here.

11. Part 4: Drawing Circuit Diagrams Make a schematic of this circuit Paste a copy of your schematic here.

12. Part 4: Drawing Circuit Diagrams Make a schematic of this circuit Paste a copy of your schematic here.

13. Part 4: Drawing Circuit Diagrams Make a schematic of this circuit Paste a copy of your schematic here.

14. Part 4: Drawing Circuit Diagrams Make a schematic of this circuit Paste a copy of your schematic here.