In this animated object, learners examine the design of a ladder circuit that provides manual control to a water pumping system. Students also study modifications to the circuit as the complexity of the system increases.

The schematic symbols of logic gates used in digital circuits are shown.

In this interactive learning object, the learner practices sizing a tank-type water heater for one- and two-family residences, townhouses, and apartments with individual water heaters.

Students review the best practices for using a ruler and answer five basic questions.