In this simulation, you can investigate the idea of the force between long straight current-carrying wires. Initially, the simulation sets up three long straight parallel wires, one passing through each corner of an equilateral triangle. The wires carry currents that have different magnitudes, and the currents are directed either into or out of the page - your job is to rank the wires based on the magnitude of their currents, from largest to smallest.
First, see if you can come up with a method to determine the ranking of the current magnitudes when you are able to change the locations of the wires. Once you have done this, and you can correctly rank the current magnitudes consistently, un-check the "Wires are draggable" button. Now see if you can come up with a new method of determining the ranking without moving the wires.