21. Voltage Data Collection for Exponentials

Using the CBL with voltage probe, a 9-volt battery, resistor, and capacitor, students collect data describing how the voltage drains from a capacitor when it is disconnected from the battery. A comparison of the ratios of the voltage reading at one second with the voltage reading of the next second reveals that the voltage is falling by a consistent percentage. Therefore, the data is described by a decaying exponential function as a model.

Technology: Graphing calculator, CBL with voltage probe, battery, resistor, and capacitor for each group of students.

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