What does a watt measure?

A watt measures the energy used per second. It quantifies the rate at which energy is consumed or produced within an electrical circuit. Specifically, one watt is defined as one joule of energy used per second. This unit is crucial in understanding how much power an electrical device uses, allowing consumers and professionals alike to assess energy consumption effectively. For instance, when you see a light bulb labeled as a certain number of watts, it tells you how much energy it will consume when it operates for one second.

In contrast, the flow of electric current refers to the amount of electric charge passing through a conductor in a given time, measured in amperes. Electrical resistance measures how much a material opposes the flow of electric current, described in ohms, and the pressure of electric current, which is often discussed as voltage, measures the potential difference that drives current through a circuit. Together, these concepts interact within Ohm's Law but are distinct from what a watt specifically measures.