### Answer to sTEm–at-Work Puzzle #51: Heater Filament Replacement

Analysis
Yet another puzzle with the same math theme:  The straight line and its slope .  However, this time the technician is working with a graphic that provides slopes that are the inverse of the way high school typically presents that information.  This is not an uncommon situation, so it is important that when dealing with slopes students have an understanding of what the slope is saying and what the inverse of the slope is saying.   In this puzzle, high resistance (impedance) means more heat. The resistance is determined by Voltage/Current calculations.  The graphic presents the results from Current/Voltage calculations.  Thus, high magnitude values for slopes on the I/V plots below classify wires with low resistance.  This means that if the same voltage is applied across Heating Element HE-5-1 and Heating Element HE5-2, filament HE5-1 will give off less heat.  This is not the optimal selection if you want the most heat possible from the filament selection.

Question: The technician should select heating element HE5-1.  YES or NO