U9A1: Introduction to Current Electricity (Part 1)

Part 1: What is an Electrical Circuit?

Unbroken, no gapsPathway for mobile electrons to move

Contains Mobile Electrons

Question 1: What is an electrical circuit?

Part 1: What is an Electrical Circuit?

Question 2: Is this copper bracelet a circuit? Justify.

Question 3: Is this gold bracelet a circuit? Justify.

Part 1: Useless vs. Useful CircuitsQuestion 4: Just because a circuit meets the technical definition of a circuit doesn’t mean it is a useful circuit. Compare the two circuits shown below. • Which one is useful (as a circuit) and which one is useless? • What is the useful circuit doing? • What does the useful circuit have that the useless one doesn’t?

Part 1: What Do All Useful Circuits Do?

Transfer Energy!!Energy Here

Transferred Here

Part 1: Current Electricity Transfers Energy

Question 5: According to the state of Washington, our local power company, Puget Sound Energy, generates about 40% from hydroelectric sources and 25% from coal-fired power plants. Do some quick research online to answer the following questions: • Identify the location of one of the hydroelectric dams used by PSE. Determine

the distance from this dam to Renton.• Identify the location of the coal-fired power plant used by PSE. Determine the

distance from power plant to Renton.

Part 2: Introduction to Phet’s Virtual Circuit Lab

From our class website, open the “Electric Circuit Virtual Lab” simulation. If successful, you will see the screen below (sometimes it takes a while to load):

Part 2: Practice Building Circuits in the Virtual Lab

Circuit 1: In the simulation, build the circuit shown here. When you are done, move on to the next slide.

Question 1: Open the switch in your circuit. Is your “circuit” a circuit within the technical definition we used earlier in Part 1? Why or why not?

Part 2: What’s Moving in The Circuit?

Question 2: Close the switch and observe. What do the blue sphere’s represent?

Question 3: Where are the blue balls when the switch is open? Closed?

Question 4: While the switch is closed, examine the lightbulb. Based on your observations, does the circuit include the bulb filament? What is the evidence?

Part 2: What’s Moving in The Circuit?

Question 5: The light bulb in the virtual circuit represents an incandescent light bulb. Why doe you think charge moving the filament makes the bulb emit light?

Question 6: Suppose the bulb in the circuit is a 5-watt light bulb. How much energy does the bulb emit per second? How much energy do you think the battery provides to the circuit each second? Justify.