Envision a long rectangular block made of a resistive material (playdough made with sugar, rolled into a long rectangle), that has a measured resistance R when put into a simple circuit with a battery and the wires attached to each end. Now cut the resistor lengthwise down the middle.
1) If the two halves are now wired in parallel, what happens to the current in the circuit? What is the resistance of each half? The total resistance of the two halves in parallel? Provide a detailed physical description of what has happened, and why this makes sense (use words and pictures as needed, graded on quality of explanation as well as correctness).
2) What if we instead wire the two halves in series? Give a detailed physical explanation.
3) To make a larger resistor from the playdough, do you need more or less material? Is there more than one way to increase the resistance? Explain.
4) Now make a set of 4-6 playdough resistors, each of different cross section and length, and stick them end-to-end to make one long non-uniform resistor**. Draw and label the resistor, and below it plot the voltage as a function of length along the resistor. From the shape of the voltage graph describe how you can find the resistance in each section.
** Just draw out on paper, no need to make sugar doped playdough though that would be super cool.