- Summarize the functionality of circuits - Review first moon observations and update moon observation log - Interpret the meaning of shadows cast by a gnomon on a sun shadow plot TODAY’S OUTCOMES: SUN AND MOON ELECTRICITY

IF YOU MAKE A MOON OBSERVATION, SUBMIT IT ONLINE RIGHT AWAY! (You can always “update” your submission before the due date....) I want to know who’s made observations on their own each day, so I can generate class participation!

Too much electrical current is what causes a circuit breaker to trip - circuit breakers are placed in a house’s wiring to prevent a fire if the current gets too high (for example, in the case of a short circuit). > If you plug in too many things, the circuit breaker will throw. What is it that makes the circuit breaker unhappy? Why do they put circuit breakers in the house’s wiring?

What voltages do most household appliances require? What typical currents do most household appliances operate at? Some devices, like cell phone chargers and electronics (especially computers) can be damaged by more than about 10 Volts. How can these be plugged into 120 V outlets? Most require ~120 V (some exceptions, like clothes dryers, have special outlets for higher voltages). Current varies but not TOO high - more than A total will trip most house circuit breakers. Such devices have special plugs that transform the voltage yet again to a lower value. HOMEWORK REVIEW

Cheryl is correct - the light bulb will not be any brighter, but the batteries will last a lot longer. > Some students are discussing the circuit shown at right, and comparing it to the usual circuit that has just one battery. Alex says, "This is the usual arrangement of two batteries in a flashlight." Bill says, "The light bulb will be brighter than with one battery" Dan says, "Nothing will happen to the battery on the left at all." Eva says, "This isn't a good idea, because it will use up the two batteries just as fast as the usual circuit with one battery." Cheryl says, "The light bulb will not be any brighter, but the batteries will last a lot longer." Flossie says, "This is a very bad idea. It will quickly ruin the batteries." Do you agree with any of them, or are they all wrong? Voltages of batteries only add together when the batteries are in series; two (or three or four....) batteries in parallel supply the same voltage as a single battery.

- How devices and switches are attached in a household circuit - Be able to identify elements connected in series and in parallel within a complex circuit - How batteries behave in series vs. parallel WHAT YOU ARE EXPECTED TO KNOW:

- Summarize the functionality of circuits ✓ - Review first moon observations and update moon observation log ✓ - Interpret the meaning of shadows cast by a gnomon on a sun shadow plot TODAY’S OUTCOMES: SUN AND MOON ELECTRICITY