The Magic School Bus and the Electric Field Trip is the ninth book in the original book series.
What is electricity? How is it made? In Ms. Frizzle's class, there's just one way to find out--a field trip on the bus! After experiencing firsthand how a power plant makes electricity, the class shrinks small enough to squeeze through the power lines. They learn how electric current travels through the town and how it lights up a light bulb, heats up a toaster, and runs an electric motor.