TODAY’S OUTCOMES: - Review the operation of series circuits and electric current - Study and measure voltage and current in electric circuits - Construct and operate a simple battery ELECTRICITY

GRADING OF ELECTRICAL CURRENT, PART 2 5 points: 4 - Correct outcome for each circuit in either switch position (2 per circuit, 1 per switch position) 1 - Clear and complete expression of ideas

14. Here are two more ways to connect the batteries, the motor, and the switch. These are not good for much; in fact, one of them is a bad idea altogether. What do they do? In circuit D, the motor runs normally when the switch is in the “up” position, but the motor does not run at all when the switch is in the “down” position. The “down” position creates a short- circuit, a potentially dangerous situation. In circuit E, the motor again runs normally when the switch is “up”, and does not run at all when the switch is “down”. This is because when the switch is “down”, the batteries are arranged such that the positive ends are both adjacent. Reversing the direction of either of the two batteries in E would result in a circuit in which the motor runs faster when the switch is “down” than when it is “up”.

WHAT DID YOU LEARN IN THE LAST ACTIVITY? Take 60 seconds - each group come up with the most important and/or interesting thing you learned (Q.13) - How to construct a series circuit given any number of batteries and electrical devices - That electric current must remain constant at all points in a series circuit - How placement of batteries and electrical devices in a series circuit affects the current WHAT YOU ARE EXPECTED TO KNOW:

– + 1 battery BATTERIES IN SERIES: AN ANALOGY TO SIPHONS + + As you read about and measure current and voltage in today’s activity, think about what the proper analogies are to these quantities in a siphon system! – – + + – – 2 batteries

One last look at a circuit studied in class w/ water siphon analogy: LED light bulb + – AB We should recall that the LED (B) was MUCH brighter than the light bulb (A). How does the current through A compare to the current through B? + – A B Using a siphon analogy (right), even though we don’t know the shape of the tube at A or B (black boxes) we know the flow rate must be the same along the whole siphon tube, as long as the flow rate remains constant.... The current through the the whole circuit is the same. (Current through A = Current through B.)

TODAY’S OUTCOMES: - Review the operation of series circuits and electric current ✓ - Study and measure voltage and current in electric circuits - Construct and operate a simple battery ELECTRICITY