Subject Matter

• On the continuum of insulators and conductors, some materials are "in between." With enough "push," or voltage, the electrons in a material flow along it, but it is difficult for them to do so.
• These materials are called resistors.
• Resistance can be thought of as an impediment to the flow of the current.

Causality

• Resistors are passive causal agents. For instance, a resistor passively causes a bulb in a circuit to light by making the path of the current more difficult. Because resistors are passive, people sometimes forget to think about them when assembling the causal story of a simple circuit.