sTEm-at-Work Puzzle 30 Answer

Voltage response of photovoltaic panels systems

This puzzles presents math and technology ideas. From the math perspective the slope of the two plots are the same so the graphs are correctly presented as parallel lines. However, the position of each line is determined by the intercept value on the Ordinate. In this case, the intercept of PP #2 is 3.5 and should cross the y axis above PP #1. In addition, the values on the y axis are not identified but can be deduced. This will allow a segway into a discussion about scaling an axis. (There is not enough information to do that exercise on the abscissa.) From a technology perspective, the negative sign on the photovoltaic data is as expected. This fact will allow an introduction into solar heating panel systems. The efficiency response of solar heating panels goes up with temperature while the efficiency of the photovoltaic goes down. Thus, the puzzle also allows a discussion of the science involved in both technologies.

Are the two plots correctly identified?               No