DL-Circuits

Demo - Ohm's Law - I connect a light bulb to a power supply in series with a slide wire rheostat.  I show the effect of more and less Voltage (Voltage like pressure) and the effect of more and less resistance.

Demo - Three Light Bulbs - Given the circuit diagram, the students predict the effect of turning on light bulb 3 on the brightness of light bulb 1 and 2.  I have them vote and raise their hand.

Lab - stuff

Lab - Resistance of a wire.  Students gather Current vs Voltage data for a piece of NiChrome wire.  They make a graph with generous error bars, and put a linear model through it.  Then they estimate the uncertainty of the slope by putting min and max slope lines through the data.  This data is Ohmic - constant slope, 0 y intercept.

Like this: https://sites.google.com/a/ttsd.k12.or.us/tuhsphysics/home/htp-ib-physics/currents-and-circuits/resistance-of-a-wire

or like this: https://sites.google.com/a/ttsd.k12.or.us/tuhsphysics/home/htp-ib-physics/graphing-prelab

Lab - Internal Resistance of a Battery.  Students gather Voltage vs Current data for a battery under various loads (currents).  As the current increases, the terminal voltage of the battery decreases, and they use this to determine the internal resistance of the battery.  

Help site: https://sites.google.com/a/ttsd.k12.or.us/tuhsphysics/home/htp-ib-physics/currents-and-circuits/internal-resistance-of-a-battery-lab